As a Death Trope, several if not all Spoilers will be unmarked ahead. Beware.
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Genderflipped in Naru Taru. Takeo Tsurumaru impregnates several girls in the course of the story. In the second-to-last episode of the manga, he has sex with main girl Shiina Tamai after she tells him that she loves him. Soon... he dies. Shiina, along with her Shadow Archetype Mamiko, makes it to the end.
X1999. Sorata and Arashi. Inverted because he dies - first in the movie (though she follows him later), later in the TV series. He's still alive in the manga, but it's a sure thing he'll die sooner or later.
In a subversion, it's less about the sex than it is that Sorata, even before the story begins, was destined to die for a woman. Sorata didn't know who he would die for or how; he just jokingly said that, since he absolutely has to die for the sake of a lady, he'd like to die for a really pretty girl. It was many years later (which is the beginning of the story) when he actually met Arashi; knowing that You Can't Fight Fate, he decided to die for her.
Also genderflipped in Trigun, with Nicholas D. Wolfwood and Milly Thompson. He dies in the same episode he sleeps with her. She makes it to the end.
In the Full Metal Panic! novels, apparently, after all these years, Kurz Weber finally manages to get it on with Melissa Mao (after years of Slap-Slap-Kiss). He dies during his very next mission. But it's ultimately averted! Guess who's back after being rescued by the Spetsnaz in the penultimate volume of the novel series??
Macross Frontier: Sheryl Nome and Alto Saotome have sex not long before battle and then, one is dead/missing and the other has a terminal illness. In the series they both get better, in the movies, this is the end!, Or is it?
Iason Mink's and subsequently Riki's deaths in Ai no Kusabi are a direct result of the former's refusal to let the latter be in order to continue having forbidden sex.
One early client of Fran Madaraki ends up like this after Fran saves his girlfriend by making her part insect. Apparently the species of insect in question instinctively eats its mate.
Required by law in Ooku: The Inner Chambers that the first man to sleep with an unmarried Shogun (Shoguns being female in this timeline) be executed for 'causing harm to the Shogun's person'. So ordered because Iemitsu the Younger's first time was via rape, and she couldn't understand that it's not always like that.
Yoshimune is horrified to find out this law exists when she becomes Shogun and inadvertently sentenced Yunoshin to death by choosing him to sleep with her, and plans to rescind the law as soon as possible. She employs Loophole Abuse to spare Yunoshin, by agreeing that he died. The tradesman Shinkichi that happens to look like him? Well, that's just coincidence.
In a roundabout way, this applies to Emonnosuke. Yes, he's had sex plenty of times before, but when he had sex with Tsunayoshi, it was the first time he had done it for pleasure, not just to attempt to conceive a child. It was also the first time he slept with someone he loved. He dies the next day of what is implied to be an aneurysm. Tsunayoshi lives for a few more years after that.
Played with in Warren Ellis' Black Gas. The main characters avoid being turned into zombies because they go off to have sex in the remote mountain cabin. Too bad they eventually died anyway.
In the X-Wing Series comics, Ibtisam dies in the same issue that she and Nrin finally officially become a couple. Feylis and Avan, on the other hand, make a no-dying pact, and they both live.
In the Elfquest spinoff New Blood, the villainous rock-shaper Door seems impossible to defeat until the jackwolf-rider Dodia beats his brains out with a club. As Door and Dodia had just recently Recognized one another, Door took it for granted that she wouldn't be able to hurt him; because they'd already had sex and conceived a Recognition-sired child, however, she was no longer biologically compelled to be his mate and could fight back against his evil.
Blue Eyes is an assassin who lures men to their deaths via seduction.
When Marv has sex for the first time, it eventually leads to his death.
Ava Lord uses a mixture of sex and Wounded Gazelle Gambit to get men to do her bidding, often leading them to their demises.
Narrowly averted in the Blackest Night arc. Writers initially planned to have the current Firestorm, Jason and his girlfriend Gehenna, doing a make-out session prior to Gen's death. This was later changed to a quiet conversation about getting married and having kids. Then they changed their minds and had it re-drawn into the make-out scene, but this was fortunately lost somehow and they ended by putting in the conversation.
In Hack/Slash, slashers are, for whatever reason, often attracted to teenagers engaging in "debauched behavior". There's easily a dozen ready examples of teens getting offed as they're about to have sex. Cassie even tried to initiate a make-out session with Skottie Young to lure a slasher to them, lampshading the trope when he rebuffed her. Obviously, this is all due to the prevalence of the trope in 80s slasher flicks, which the series is largely inspired by in the first place.
Justification: In the first Friday the 13th (1980), the killer, Pamela Voorhees, specifically targeted the people who were having or going to have sex, because the two camp counselors who were supposed to be monitoring her son Jason Voorhees when he drowned as a child were too busy getting groiny with each other.
Although there are later claims that the counselors tried to catch Jason who ran off and fell into the lake becausehe saw them going at it.
A most notorious moment in the second movie is where two teens got killed while in the middle of getting it on. Jason killed them shiskabob style by skewering them both with a spear.
A significant lampshade is hung on this trope in the tenth film in the series. In a virtual reality simulation meant to distract Jason, a pair of scantily clad teenage girls exclaim (among other things), "We love premarital sex!" He proceeds to kill them with each other.
Done heavy-handedly in the 2009 reboot; every character who has sex, or wants to have sex, or fantasizes about having sex, or is a creepy redneck who has sex with mannequins gets killed. There are a few others, of course.
Subverted in Cherry Falls, which had a serial killer that targeted virgins. When the Genre Savvy town teenagers figure this out, they decide to throw an orgy... which the killer, having gone completely Ax-Crazy (complete with axe) by the end, crashes and massacres.
In The Day After Tomorrow, two workers at the local weather service station are making out passionately on the couch when tornadoes strike Los Angeles. In the chaos that ensues, they die, while the Mexican janitor (who was diligently cleaning the floors while the people who were supposed to be monitoring the weather were making out) survives.
Lampshaded in the movie Scream (1996), where this is the very first of the rules posited by Genre Savvy horror geek Randy Meeks for successfully surviving a horror movie. The other two rules cover drinking and doing drugs, and saying that you'll be right back. He later gets killed in the sequel, and it's revealed that he spent a night with "Creepy Karen" before getting whacked.
Not to mention it's hilariously subverted when Sidney bangs the damned killer and gets to survive the movie!
Angelina of the third film reveals that she employed the Casting Couch to get the role of Sidney in Stab 3... then she dies seconds later.
In the fourth film, it's revealed that Jill lost her virginity to Trevor, pushing their position as Sidney and Billy expies further. Later, Jill is revealed as the killer, and she offs Trevor shortly, making this the exact inverse of the Sidney and Billy example, right down to the sex of the killer.
More or less every B-Movie and thus, rightfully parodied in the "Thanksgiving" segment of Grindhouse.
Used in the original Halloween (1978), where three of the five victims had just had sex, and the fourth was on her way to do so. It's heavily implied, however, that Michael Myers has some severe issues with sex, and the selection of victims is not at all coincidental.
In an interview with AMC, John Carpenter (the Director) states "I have been accused of ending the Sexual Revolution, and for that I sincerely apologize."
The same happens in the remake: Everyone seen having sex dies horribly. Most of the other victims probably weren't virgins either (this pattern is so glaringly obvious in the movie that it must have been intentional). They even went out of their way to mention Laurie hasn't gotten laid. Although, the trope is surprisingly averted with Annie, who actually survived her attack to appear in the second movie and THEN die.
In the 1970s The Day of the Jackal, The Jackal meets an attractive married woman at a hotel, has a torrid affair with her, then later discovers her address and goes to her home. When she asks him about what he's doing, because the police were looking for him, and he's driving a car with local plates, which means she knows he stole it, and if he'll just tell her, she won't say anything, he breaks her neck.
Parodied in Illuminatus!, wherein the British agent Fission Chips leaves a trail of dead Eurasian girls wherever he may go.
Played straight and averted in Live and Let Die. Rosie Carver is killed after Bond seduces her. Solitaire, who is supposed to remain a virgin to retain her psychic powers, is also seduced by Bond and was supposed to be sacrificed in a voodoo ritual, but Bond saves her, firing a Smith & Wesson Model 29 .44 Magnum revolver in the process.
Inverted in The Man with the Golden Gun. The assassin Scaramanga has sex right before he kills someone that he's been hired to kill. (Bond notes that some matadors do the same thing before a bullfight.) The Trope is played straight, however (maybe even doubly so) because Scaramanga later kills his lover after she double-crosses him and helps Bond.
In Snakes on a Plane, a couple sneaks into the bathroom to have sex. They are the first to be killed by the snakes. Their drug use may have contributed, too.
Interestingly, the slasher film did not always contain this trope: in the 1974 Canadian film Black Christmas (1974), the heroine is pregnant, though the movie ends with her alone in the house with the killer.
The first victim is also described as a "professional virgin."
In Boa vs Python, the python stalks a teenage couple that is having sex, and actually licks the girl, who, because her eyes are closed, thinks it is her lover. Then the python, which should be a constrictor, bites them squarely in half.
Inversion: In Once Bitten, the hero is targeted by the vampire Countess because he's a virgin. He and his girlfriend end up having quickie sex in a coffin, rendering his blood unsuitable for her needs.
Piranha Part Two: The Spawning's opening scene had a couple discussing where they failed to have sex because the guy found fault in everything. The hotel room was too dry, the beach too sandy, and the boat too uncomfortable. They then go scuba-diving into a shipwreck and decided to have sex, you know, nothing better than that, right? Well, okay, the killer piranha did kinda ruin the mood.
In Taken, as soon as the slutty best friend says she's going to have sex with a random French guy because "Who cares? He's hot!", it was obvious she was a goner.
In the film Tormented, a schoolboy who killed himself because of bullying comes back from the dead to take fatal revenge on the bullies. One of them decides to go to the cemetery and dig up the killer's body, but is sidetracked by having sex with his girlfriend while his car is parked there, which turns out to have been a very bad idea because the killer drags him out of the car and castrates him by repeatedly stomping on his genitals, leaving him to bleed to death. Ouch.
Two of the youngsters that stop by in the Mario Bava movie Reazione a Catena who are speared while having sex. Friday the 13th Part 2 copies this very scene, only putting the guy on top instead of the girl.
Subverted in The Godfather Part II, where Senator Geary, who hates Michael Corleone's crime-racket, is made to believe that he accidentally killed a prostitute during "weird sex-games" at Fredo Corleone's brothel; after this, the senator is indebted to Michael for covering up the incident, but is also blackmailed by him. One shot afterwards heavily suggests that Al Neri was responsible for the actual killing.
Invoked in Evolution where an Asshole Victim actually sings the song quoted at the top while preparing a rendezvous on a golf course... and is promptly eaten. Slight subversion in that the pair hadn't actually gotten around to the deed (and the woman survived).
Exaggerated into the family-friendly version of this trope: Death By Marriage. As soon as Will and Elizabeth are hitched, you know one of them is about to die.
But then subverted, and arguably inverted, when some Loophole Abuse causes that character to un-die, and the two are able to consummate in due course. (And not like that, either.) Heck, even the "family-friendly" element is subverted, because we see them putting clothes back on afterwards. (Not to mention the reveal in The Stinger...)
Inverted in Death Proof. The first group of girls, while they act fun, are surprisingly conservative, especially Arlene/Butterfly, who actually seems to have some kind of aversion to sex. They die. Horribly. The second group, on the other hand, are very open about their sex lives ("He likes to watch me pee"), and Kim at one point in the final chase scene yells "I'm the horniest mother-fucker on the road!" Not only do they live, they kill Stuntman Mike.
Played so straight it's almost a parody in Jennifers Body, where the title character uses the promise of sex to lure boys into places where she can eat them. It's revealed though that the whole "demonic possession" thing gets kicked off only because its perpetrators thought they had gotten their hands on a virgin sacrifice.
Sarah Connor's roommate in the first Terminator movie.
And Kyle as well, after he serves his purpose by impregnating Sarah with John and delivering her to the point where she can defend herself from then on (partly because he's already damaged the Terminator so badly himself).
In the fourth Final Destination movie, Hunt has steamy sex by the pool and shortly after dies a very gruesome death by being sucked into a high pressure drain hole. It doesn't help that he was a Hollywood skeptic that was warned about some weird stuff going on... or saying earlier that if he was going to die, he was gonna get laid first.
In The Towering Inferno, Dan Bigelow and his secretary/mistress die almost immediately following a tryst in his apartment.
Although there's no actual sex, the sultan's death in The Thief of Bagdad has overtones of this — he's given a mechanical woman as a gift, who dances seductively in front of him, and when she goes to embrace him, "she" stabs him in the back.
In the shlock blood-and-boobs horror film Piranha 3D, most of the victims are promiscuous spring breakers. A pornographer gets his penis bitten off by a piranha, a woman is sliced in half by a high-tension cable (which first removes her bra, then her entire upper torso), a girl gets her hair entwined in the propeller of a speedboat and has her face ripped off — might be one of the definitive "death by sex" compilations.
Averted in Ghostbusters. It's strongly implied that the final event that allowed Gozer to come to New York (an event that would've caused the apocalypse if the Ghostbusters hadn't killed her shortly afterwards) was Dana having sex with Lewis. It's an aversion because both Dana and Lewis were possessed by, respectively, the Gatekeeper and Keymaster rather than being voluntary participants, and because both of them survive the film.
In Starship Troopers, Dizzy Flores dies within 24 hours after finally having sex with Rico. Something she'd been wanting since the beginning of the movie. The sex, not dying.
Inverted in Norwegian slasher Cold Prey / Fritt Vilt. The virgin who just refused to have sex with her boyfriend is the first one to die.
In Cabin Fever, a flesh eating disease scares off most of the teenagers spending their break in a cabin in the woods. When only two are left behind, the requisite horror-flick babe figures that, seeing as they're doomed to die anyway, she and the hero might as well go out with a bang. Only after the horny hottie gets his pork in her pouch does the guy question why they aren't using a condom. Of course, the woman tells him not to worry because "She's healthy." Oh good! Seeing as how all their friends had come down with this deadly illness, I was afraid she might be sick, too. No need to worry about that sinister soundtrack playing as she grinds you into the mattress, pal... Or those sickly red rashes that just appeared where you grabbed her back while you blew your load. But, just to be on the safe side, you should probably rinse off the salami with some Listerine when you're done.
The entire plot point of the film, Body of Evidence, starring William Defoe and Madonna.
Played for laughs in Wacko at the Halloween Prom when the Lawnmower Killer shoves Tony Shlongini's head into the garbage disposal in the school cafeteria; the cafeteria matron then interrupts the murder to teach him how to use a garbage disposal properly. The Lawnmower Killer then runs Tony's date, Rosie, who's wearing only a whipped cream bikini, through the cafeteria's conveyor-belt dishwasher.
In Harm's Way: Everyone connected to Eddington via sex by two steps of separation or less ends up dead by the end of the film.
In Fathers Day the very act of fathering a child (that is, impregnating a woman) makes you a target for the Father's Day killer.
Ex-Heroes has Cairex the Demon-Human Hybrid die in the backstory due to getting a blow job from zombie Jessica Alba. No one is sure how to react to this story when they hear it.
"Sex equals death" is the main theme in Kurt Vonnegut's short story "Welcome to the Monkey House," in which a dystopian society prevents people from having (or enjoying, if they do try to have it) sex. The "villain" responds by basically raping women to force them out of their belief that sex is wrong. It works.
In Arthur Machen's The Great God Pan, a sinister woman drives prominent men to madness and suicide. The unspeakable horror they experienced is strongly implied to be sexual in nature, although Victorian propriety prevented Machen from elaborating.
In Stephen King's short story "The Raft", four college students swim out to a raft in the middle of a remote lake. A mysterious oil slick-like creature appears, and devours two of them; the first one touches it, the second steps on a crack on the raft and gets grabbed by his foot. Hours later, the remaining two (a guy and his girlfriend) end up having sex; the girl's hair falls off through the cracks of the raft and the creature absorbs her.
In the second Night Watch book, Alisa and Igor have sex, then discover who (and what) each other is. Light magician Igor then kills Alisa for being a dark witch, then goes into a depression and ultimately lets himself die in remorse.
In Jaws, the book actually kills off the character Matthew Hooper during the cage scene. Earlier in the book: he was having an affair with Brody's wife, Ellen. She avoids the trope by never being in the water. The first victim in the book was taking a postcoital swim.
Lampshaded in The Dresden Files novel Proven Guilty via Dresden's description of some of the monsters in the films shown at Splattercon!!!. One of them is supposed to be a monster that hunts the wicked, which apparently includes anyone drinking or having sex.
In Vampire Academy's third volume, Shadow Kiss, Rose and Dimitri finally give in to their passion for each other... And right after the school is attacked by Strigoi and Dimitri is "taken." Right when they whipped it out, you knew something bad was going to happen to one of them, at least, since a huge plot point of their relationship is that it's forbidden.
While it is not a quick connection of "sex then death", Thomas Hardy's Tess Of The D Urbervilles is certainly doomed by sex. The titular character is either raped or seduced (it's slightly ambiguous, but most assume rape) early in the book by a distant relative. This completely destroys her life and sends her on an ever-increasing spiral of despair for the rest of the book, repeatedly rejected because of being Defiled Forever, until at last she murders the man who deflowered her and is hanged for it.
Also, while one may argue whether it happened or not, it's implied Tess and her husband Angel, who once abandoned her just because she was not a virgin then came back and tried to rescue her from execution, consummate their marriage in their hideout. And their hideout scenes are supposed to be those moments of (false) hope.
Because of a massive subversion of STD Immunity in the world of A Brother's Price, sex with non-virgins is not well thought of. Men are rare enough that those who are not made into husbands are crib captives, made to service women for ten crowns a night in the hopes of impregnating them. Various different cribs have different reputations, some thought to be clean, others not; to someone of noble status, visiting even a 'clean' one is social suicide. There are stories about a married woman "getting an itch to try a crib", catching something other than a child there, and spreading it to her husband, who spread it to his other wives and any children they conceived, to the point where the entire family was killed.
Never Wipe Tears Without Gloves: In the eighties gay men were considered to have brought AIDS on themselves because of their sexual behaviors. The book focuses on this quite a lot and author Jonas Gardell makes a lot of references to actual articles written in Sweden at the time and actual things politicians, religious leaders and other public figures were saying and suggesting. Especially heartbreaking when the book quotes actual newspaper headlines that mention the tragedy when an innocent (i.e., a heterosexual who got AIDS through blood transfusion or heterosexual sex) dies of AIDS.
Greg Egan's Orthogonal trilogy plays this universally and chillingly straight: For the protagonist race, sex triggers immediate reproduction, which consists of the mother fissioning into four children. So it's a necessary part of biology... and also murder.
HBO's Game of Thrones certainly depicts a world in which many beloved characters die. As a lead-in to the Red Wedding, you know the young couple Robb Stark and his newlywed Talisa are screwed when they are shown together happily... screwing. As a bonus, their deaths are foreshadowed the moment they decide to name the unborn child after Robb's late Father, Eddard Stark.
VH-1 did a special regarding horror movies (I believe as a tie in to Scream 3.) Throughout the show, they listed "Horror Movie Rules." One of the top rules was simply, "Virgins live, sluts die."
This enduring trope may have had its first instance on TV with the Alfred Hitchcock Presents episode aptly entitled "Coming, Mama" (episode #217, originally aired 4/11/61).
Although those girls all recovered in the end, as opposed to many victims of the week.
Mini Series and book example: in Porterhouse Blue a middle-aged bedder, who senses a college's only research graduate student's secret obsession for her, sneaks in his room in the middle of the night and rapes him. However, moments into the act they both explode because, while sneaking in, she lit the gas without knowing the chimney was blocked. (For reasons too complicated to explain, the blockage consists of gas-filled condoms, I kid you not, so the explosion is pretty spectacular.)
This happens almost every episode in CSI: Crime Scene Investigation. If two characters are shown having sex, and it's enjoyable and unwed and not in the missionary position, one or both of them are doomed. This has more to do, however, with the fact that any character outside the main cast whose personal life the show delves into is doomed, regardless of what they're doing.
Done entirely straight with two of the regulars on CSI NY. That's not Danny and Lindsay, yet. It was Flack and Angell.
Also common in House, where sex and sexually transmitted diseases are routinely the cause of a number of horrific medical cases, up to and including heart failure, car crashes, paralysis, life-threatening pre-teen pregnancies, and even African Sleeping Sickness.
"Sex Kills" is the title of one of the episodes.
Subverted in one episode, where we're led to believe that a woman's sexual promiscuity may have led to her illness, but it turns out that the cause is something completely unrelated that she couldn't possibly have foreseen.
Subverted in another episode where Cameron assumes the (male) porn star they're treating is sick because of his profession, but it turned out to be caused by his over-sanitary childhood instead.
The first two times LOST depicted couples having sex on the island, the female of the couple (Shannon, Ana-Lucia) was shot and killed later in the same episode; the latter was the one who killed the former (accidentally).
Also Libby, whom it's strongly implied was about to do the deed, if she hadn't already.
Also, sleeping with Sayid is practically a non-stop ticket to the afterlife. In fact, this is what kills Shannon. He later marries Nadia, and actually ends up shooting Elsa himself.
A running joke on the Television Without Pity recaps for Supernatural is that every woman that has sex with Sam must, by rule, die. Began with the Pilot, confirmed with "Heart" in which Sam is forced to kill the first woman he has brought himself to sleep with since his girlfriend's flaming death and in recent episodes seemingly subverted until we find out that it is actually a demon in a dead body, so she was already dead!
Ruby should still be added to Sam's sex hit list, now that she's been skewered with her own knife. That leaves Sam's track record at 3 out of 4!
Subverted later in the season. The next woman Sam has sex with experiences no karmic retribution whatsoever we are led to believe that she is the demon they're after, until it is discovered the real demon is the guy Dean is cosying up with.
Also heartbreakingly inverted in the middle of season 5, when Jo refuses to sleep with Dean on their 'last night on Earth', saying she'd prefer to keep her self-respect... and dies later in the episode anyway.
Disaster occurs after the first time Angel and Buffy sleep together. Enter Angelus, who then kills Jenny Calender and tries to destroy the world.
Xander attracts quite a number of demon girls who want to have sex with him and kill him. At once for the first case, the substitute teacher who turns out to be a female mantis.
The prevalence of this trope is lampshaded in Angel after Cordelia's first brush with a Fetus Terrible.
Cordelia:I learned something, too. I learned, uhm... men are evil? Oh, wait, I knew that. I learned that LA is full of self-serving phonies. No, had that one down, too. Uh... sex is bad?
Angel: We all knew that.
In the first season of 24, Kim Bauer sneaks out with her friend Janet York to meet up with a couple of college guys. Janet has sex with one of the guys while Kim just makes out with the other one. When it turns out the college guys are set to kidnap the girls, it's the start of a pretty bad day for Kim, but Janet? She gets her arm broken, doped up on heroin, run over by a car, and is finally suffocated to death.
In Season 8, Renee Walker is killed by a sniper after having sex with Jack.
Shawn: I'm as sick as you can get without actually dying.
The premise of the comedy series Laid. A woman discovers that all the men she's ever had sex with are dying. In the order she slept with them. All in really random ways, like getting hit by a car or getting an aneurysm or getting hit in the head with an indoor cricket ball.
On Heroes, Elle and Sylar entertain a brief sociopath/psychopath romance and immediately have sex when they realize that the second eclipse was blocking their powers. Once they regained their powers however, he murders her after they fail to murder Bennet and he realizes that their relationship had no possibility of being sustainable.
Alana De La Garza, who plays Marisol Delko Caine on CSI: Miami, has said that she knew her character was going to die when she heard that Marisol and Horatio were getting married.
In the Masters of Horror episode "Pick Me Up", a rocker and his girlfriend unknowingly pick up the serial killer Walker from the road. The girlfriend flashes her panties to Walker, pissing off the boyfriend. Walker kills them both, but the girl specifically for being skanky (and he tortures her to death whereas the boyfriend got a quick one); he actually abhors sex.
In Series/Torchwood, on the second episode (Day One) there's a sex gas alien that inhabits a young woman's body and has sex with men to remain alive via orgasmic energy, but this in turn kills the man, thus her victims literally died by sex.
"White Pearl, Black Oceans," a song by power metal group Sonata Arctica. A reclusive lighthouse keeper heads into town one night, meets a woman, and later sleeps with her. On his way home, her husband beats him so badly that he's unable to make it back to in time to light his lamp. Naturally, a ship crashes that very night, everyone on board dies, and the lighthouse keeper is so ridden with guilt that he throws himself from his tower.
Briefly treated for laughs in the video for "Sweet N Sour" by the Jon Spencer Blues Explosion. A couple are making out in a bathroom and then a monster comes out of the toilet are decapitates them.
The Bonzo Dog Doo Dah Band's "Death Cab for Cutie". Girl cheats on her boyfriend, takes a cab home, driver jumps a red light, splat. (Bit unfair on the driver, though, unless he was the one she was cheating with.)
The video for Cephalic Carnage's "Ohrwurm" is a rather gruesome and graphic rendition of this trope.
The wrong kind of sex in a lot of mythology and classic literature (premarital, adultery, incest, impulsive, etc. depending on the age) could lead to various unpleasant fates, from infertility to being turned into trees. See also Good People Have Good Sex.
For instance, in Oedipus Rex, Oedipus accidentally marries and has sex with his mother Iocaste. And just to show that sexism is timeless, guess which one of the two of them dies, and which one goes on to become a cult hero in Oedipus at Colonus?
To be fair, Iocaste commits suicide, specifically because of her learning that Oedipus is her son. Oedipus apparently thinks it sufficient to tear his own eyes out of his eye sockets.
In classic Greek theater, the hero of a tragedy was never allowed to die, but suffer greatly and live with the pain in order to grow as a person from it so this was more a convention of the theater style of the time rather than a literary choice.
And according to Aeschylus' Seven against Thebes and Euripides' Phoenician Women, his sons Etheocles and Polyneices thought of him as a curse and a pariah to the point of forcing him to step down as king, locking him away and later kicking him out of Thebes along with his daughter (and their sister) Antigone.
His father Laius abducted and raped Chrysippus (who he was the tutor of) and the gods placed a curse on his family, saying that Laius' son would kill his father and marry his mother.
Most Death by Sex tropes originate about from the fact that Scripture prescribes capital punishment for many forms of sex: Adultery, homosexuality, bestiality. Many experts now believe that this was the Jewish way of increasing their population-numbers through increased births, in comparison to other nations that allowed and encouraged other kinds of sex. When Christianity also adopted these laws among other cultures, the moral became woven into stories ever since, as An Aesop theme that "God Is Watching" and that He punishes those who choose to violate his law; this is also symbolic for the idea that such types of sex are essentially "killing" the persons in an extended sense (i.e their descendants, society, etc).
Not all violations were punishable by death, however. If neither of the lovers was married (or betrothed), the Bible commands the couple to be married immediately, unless the woman's father refused. Note, this order to get married (and pay the dowry associated with the marriage) stands whether or not a child was conceived. Oh, and a man who married his wife this way can never divorce her.
Though this also held for rape. It just about makes sense within the view at the time of women as property - you break it, you bought it, essentially. However, from the wife's point of view, when compared to spending the rest of your life inescapably married to your rapist, death by sex might be preferable. It should be borne in mind that the victim was never required to live with her rapist or ever sleep with him again.
The reason for this being that in Bible times non-widowed non-virgins had virtually no chance of being married after being deflowered, (unless already betrothed) so marrying her rapist/lover was the only way she could get married and have some status in society. Getting married was woman's only option in those days unless she wanted to be an outcast.
Not all scholars agree that homosexuality was outlawed, in fact it was more likely just talking about ritual prostitution.
Or anal sex, hence the specified "like a woman" in the passages. Other forms of homosexual acts would have been ok though.
Harpies traditionally eat their mates after sex, and in fact consider it shameful not to do so, especially if they become pregnant as a result.
In a reversal, though, Sirens are well-known for literally dying of grief and heartbreak (or just committing grief-fuelled suicide) if their mates run away or are taken from them.
Hags may or may not eat their lovers; it depends on whether they feel hungry or think it would be more "fun" not to.
Jorogumos mate with humanoid men to become pregnant, then use their poison to paralyse their lover before implanting the fertilized eggs inside of him; the jorogumo painstakingly keeps him alive and well until the egg hatches, whereupon the baby jorogumos eat their father as their first meal.
Thriae Queens need humanoid males to fertilize their eggs and produce more thriae for the hive. When their consort grows too old to be able to have sex, the custom is for the Queen to painlessly poison them, putting them into a deep, anesthetized slumber, and then eat them, after which she will seek out a new consort.
In the Broadway musical Into the Woods, the heroes split up to search for Jack to protect him from a marauding Giant. While she's searching, the Baker's Wife meets up with the Prince and has sex with him; she's crushed by the Giant immediately afterward.
Well, after she has a soliloquy/musical number that sums her mindset up as "my affair has made me more grateful for what I have but hey it was kind of nice." She's more killed by barely-repentant adultery than killed by sex, since she's a married lady with a child.
Meanwhile, by contrast, the entirely unrepentant and equally married Prince is punished by hooking up withSleeping Beauty. Then again, who was expecting something by Stephen Sondheim to be fair?
He did have to contend with a dwarf.
Dwarfs are very upsetting...
In Victorian theatre, the only accepted way for a "fallen" woman - that is, any woman who had sex outside of marriage, or had an affair - to redeem herself was to die. Preferably after seeing the horrible consequences of her actions. One notable example is East Lynne: A woman is convinced by a rival of her husband that her husband is having an affair, and so agrees to run off with him. But the rival abandons her, so she returns to her former house in disguise as a governess to her own child. When she reveals herself to him, he dies. Everyone then finds out who she is, but she falls ill and dies shortly thereafter. Her melodramatic cry on her child's death, "Dead! And never called me mother!" is still quite well-known today.
Aversion: W. S. Gilbert's 1874 play, Charity has up a woman, Mrs. Van Burgh, who was virtuous in every way, except she had never actually married her husband. She has spent all her time since his death doing good deeds, and trying to rescue other women back to the path of virtue. Victorian theatre demanded that she be ruined, and die in order to be redeemed. Gilbert allowed her to be ruined by public opinion and the hypocritical antagonist (he lectures Ruth, one of the women Mrs. Van Burgh gave a second chance to, on how abominable it is that she is being foisted on society as if she was an unfallen woman. Guess who had seduced her?) - but then both Mrs. Van Burgh and Ruth head off to Australia as traveling companions for a colonial bishop whose son is in love with Mrs. Van Burgh's daughter. You wouldn't believe the uproar this caused in the newspapers of the time, which fell over themselves trying to see which could declare the play more immoral.
Dickens used the trope straight in Oliver Twist with poor Nancy, who also was a prostitute and ended up dead.
This is less "because she's a prostitute" and more "because she hangs around with Bill Sykes." Granted, she does think Sykes loves her, and presumably has had sex with him.
Stephen Sondheim does it again in Passion, where Fosca dies three days after, um, a final bit of passion.
Romeo and Juliet would be an example, except the two secretly marry before they do that sort of thing.
Although since they marry against their families' wishes, and the story was originally meant to be a warning tale of young people who fall in love too quickly, do foolish things, and suffer horrible consequences, it still counts as an example of "death as a punishment for socially unacceptable sex".
Done after a fashion in Wicked where the very next scene after Fiyero and Elphaba have their G-rated sex scene in 'As long as you're mine' and kiss Fiyero gets beaten to death. He gets better though. Sort of.
Subverted in "Much Ado About Nothing" as Hero is falsely accused of sleeping with another character the night before her wedding. To clear her name, she fakes her death which forces all the characters who ostracized her to realize that they were wrong to mistrust her.
Speaking of Yahtzee, he's also used this trope... literally. Well, almost. Occurs in 6 Days a Sacrifice, part of the Chzo Mythos. Janine having sex with Theo was what ended up allowing John Defoe to take full control of her. By the end of it, she got impaled in the chest and literally crushed inside a wall. NEVER have sex when there's obvious signs of someone being partially possessed.
One of the more controversial things you can do in the Grand Theft Auto series, since it's introduction into the 3D world, was to be able to take a prostitute to a secluded part of whatever city your in (like in an alley or a closed off section of it), then wait until the car stops shaking. Afterwards, when the prostitute comes out of the car, you could then murder her and get the money back that you spent on the experience (since she then was programmed to return to the game world as a pedestrian that you could kill).
In Phantasmagoria 2, it's more like Death by Kinky Sex. The female BDSM fanatic is murdered, while the woman who is having monogamous vanilla sex with the protagonist and wants a committed relationship survives.
In the Leisure Suit Larry series, this trope appears twice. In the first game, sleeping with the hooker at Lefty's Bar without protection causes your family jewels to explode a minute or so later. In the second game, you can seduce the maid in your resort hotel room and sleep with her, only to have her brother (who's in the military and likes to shoot things) walk in on you.
In WhichWay, a flash adventure game, every time you end up with a naked or half-naked woman on screen, you will be ambushed by a monster within seconds.
A variation occurs in SHUFFLE!!, where one of the more magically-inclined characters you can choose erases Rin's memories of her during sex. His memory is returned to him by an act of The Power of Love, which she wasn't expecting.
In the Silent Hill series, any woman who implies that she might perform sexual favors on the protagonist will die in an agonizing way within a few scenes. It began with Maria in Silent Hill 2 and continued with Cynthia in Silent Hill 4.
Inverted in the third God of War. Aphrodite has sex with Kratos late in the game. She is the only Greek God spared of his wrath.
This is more a case of Dummied Out, as the designers originally planned for Aphrodite to pull a knife on Kratos if you went back for round two, which would end in her death, but decided against it.
In the Neverwinter Nights module series The Bastard Of Kosigan, you can go through it in such a way that every woman you make out with or have sex with dies soon afterward. Of course, being the non-linear sort of story it is, all of them but Alex can survive too.
Several quests in A Dance with Rogues, most notably the Dhorn Generals' Heads quest in the first chapter, involve having sex with someone to get something before killing them.
Fallout 3 has a house in Minefield with two skeletons embracing on a bed, indicating they may have been lovemaking when the bombs hit.
In Fallout: New Vegas, the player sometimes gets the opportunity to invoke this on others — most notably, a female main character can opt to screw and then murder Benny in his sleep! Or just make him think you're going to sleep with him in order to get him vulnerable.
After awhile of playing Kara no Shoujo you begin to wonder if maybe the writers were trying to scare teens away from sex. The first set of victims are targeted partially because of this and most of the time the main character has sex he ends up dead soon after. That or the girl does.
Happens to a seduced NPC in the Human Noble origin in Dragon Age: Origins. He or she opens the door of the playable character's room to investigate a noise and gets an arrow in the chest. However, if you choose not to seduce them, you'll find their dead body slightly further on, so the only real difference is whether or not their death occurs onscreen.
NetHack has the succubus and incubus. Without proper protection, there are quite some ways for an encounter with them to be fatal.
Slash Em Extended makes it much more likely for the encounter to cause negative effects for the player, and also adds more ways for the player to die, e.g. suddenly being attacked by the rape demon after they already took off their clothes.
ThisDumbing of Age strip provides some Conversational Troping. The morning after Dorothy and Walky's first time together, Dorothy is horrified to learn she overslept and missed a class. Walky jokingly compares their situation to a horror movie; unfortunately, he does so within earshot of Joyce.
Dr. Horrible's Sing-Along Blog: Penny dies in the third act, which was also when Captain Hammer started bragging about sleeping with her. During a PRESS CONFERENCE. While it is possible that he is lying (Captain Hammer being a total Jerk Ass, after all), the fact that Penny looks uncomfortable at his assertion, not outraged, suggests they did it.
Of course they did.
Cpt. Hammer: [singing] This is so nice; I just might sleep with the same girl twice.
"Let’s kick this list off with the cliché that’s probably the greatest reason many of us enjoy watching gore fests to begin with. Horror films always have people, specifically young adults, getting it on and baring it all. Not just eye candy, it mirrors teen fears around sexuality. As a result, most horror flicks push the parent-approved message of abstinence. Don’t believe us? Then why does the film’s always blonde quote-on quote “whore” get axed and the prudish but keen minded brunette always survive?"
In The Nostalgia Chick's review of Dantes Peak she claims that volcanoes have a sapient hatred of fornication, since the first people it kills are a pair of Skinny Dipping tourists and the hero is motivated by a dead fiancée. It also spends much of the movie "cockblocking" him and his new Love Interest.
An episode of Futurama parodies the B-movie tradition by having a robot couple making out in a car say things like "It's okay to let our guard down, even for a moment!" before being attacked by a "scary human".
This was how a lot of people outside of the gay community initially saw AIDS, before they knew more about it.
Speaking of which, this was the case of ST Ds during the eras before modern medicine; getting one was basically a death sentence until the last century. Smallpox was small because Syphilis was the Great Pox.
Général Paul Thiébault tells the story of a naïve young man called Monnet, who discovered sex at twenty with a voluptuous Neapolitan woman. What happened is anyone's guess, but twenty-four hours later, Monnet started bleeding from the nose, mouth and ears and died within a few hours.