Professor X falls in love with Shi'ar Empress Lilandra during the Phoenix Saga and becomes her consort. While their respective duties kept them from truly being together, she would still send him care packages in the form of technology upgrades for the mansion.
Dazzler of the X-Men married extra-dimensional alien Longshot, who has since their divorce gone on to make Boldly Coming a way of life.
The Marvel Universe is full of these things. Captain Mar-Vell has at least three children, none of his own species, for instance.
Not one, not two, but three of the Superhomeys obtained their powers from sex with non-humans (one a robot!). In fact, they met in a support group for it. One of them gained his powers through an alien STD.
Every single major love interest that John Stewart has ever had was an alien. He has been married to the red/magenta Korugaran Katma Tui and dated the blue Baraquan Merayn Dethalis.
And lampshaded early in the movie as the "crew" chastises Jason Nesmith for his character (Captain Taggart) doing exactly what James Kirk did in his own show. Although it wasn't made clear if it was his character ...or him, it pretty heavily implies that Nesmith is sleeping with the actresses playing the green skinned space babes. Whether his character is also sleeping with the green skinned space babes is sort of irrelevant at that moment.
The sequel, Into Darkness, has him in bed with Caitian (cat people) twins. What a stud.
Barbarella the pretty blonde envoy of an Earth that left behind such outdated concepts like violence or physical sex, gets used to both rather quickly after being introduced to them on a more... uhm, anarchic planet. She doesn't decline to try other things too. In one memorable scene, Durand-Durand tries to kill her with his orgasm machine, but she overloads it.
Interspecies prostitution is mentioned in District 9... with aliens who look like broadly-humanoid shellfish. The protagonist is falsely accused of having contracted an alien STD.
Early into Clerks II, in Jay and Silent Bob's first scene, Jay talks about this.
Before Alien: Resurrection was released in theaters, there were rumors of a sex scene between Ripley and an alien. Sigourney Weaver, when reached for comment, said "No. That's Alien 5". There was however one scene of Ripley being carried by an Alien that played with the subtext. The studio wanted to cut it because of the implications, but Weaver refused.
In Men In Black II, an entire subsection of the plot focuses on J discovering that Lara is a Zarthan yet still being in love with her. It is also heavily implied that K had a fling with her mother. The series as a whole seems to enjoy playing with these ideas.
The "bodily fluid" problem is a real one in Alien Nation. The bad guys among the aliens are shown to have a taste for human women, but the aliens' flesh is corroded by salty water...
Jake in Avatar. Justified, considering the fact that one, it took quite some time to get to that particular point, and two, he was in his Na'vi body.
The common method of demonstrating your peaceful intentions with whomever you happen to run across is to have sex with them, also known as Rishathra.
Made easier on a world where just about every race encountered is a far-evolved subspecies of humankind.
Also used as birth control since the various species are no longer closely enough related to produce children.
The first people they meet in the second novel reveal they're incapable of Rishathra.
Both Louis and Teela end up doing it with Ringworlders. One of the reasons Halrloprillalar wants to leave Ringworld and go to Earth with Louis is because she thinks that humans know very little about sex (she's a professionally-trained ship's whore).
Of course the Martians are divided into monstrous four-armed Green Martians and heavily-tanned-human Red Martians. Guess which one the Princess is! (Although she does still lay eggs, raising some unanswered biological questions...)
Inverted in Octavia Butler's Xenogenesis series, where it's the aliens that want to crossbreed with the humans and every other race they come across. Given that they're all passive-aggressive tentacle-covered anemone-like things, this takes some work.
James Tiptree, Jr's story, And I Awoke and Found Me Here on the Cold Hill's Side - albeit with rather unfortunateimplications as to the eventual fate of the humans involved.
Used in Erich von Daniken's nominally nonfiction Chariots of the Gods to argue that Boldly Coming is obviously the first thing we'd be doing if we were traveling to unknown planets. The Ancient Astronauts just thought of it first.
Subverted in The Gods of Xuma, where the human explorers discover, with some frustration, that those good-looking humanoid aliens aren't "mechanically" compatible.
Technically Golan Trevize, except that all planets are inhabited by humans.
"Erotomaniac? Come, Bliss. Twice on this entire trip. Twice!"
"We were only on two worlds that had functioning human females on them. Two out of two, and we had only been a few hours on each."
If you think about the breadth of cultural and political differences between the humans on the various Foundation worlds, the trope probably does hold.
This trope is definitely Older Than Feudalism; in Lucian's True History, some of the narrator's traveling companions have sex with tree-women on a remote island, and end up stuck to them.
In L. Sprague de Camp's The Hostage of Zir, one of the characters comments that The Bible forbids fornication, sex with a human you're not married to, and bestiality, sex with a dumb animal. But it says not a word about fun with a Green-Skinned Space Babe on the planet Zarathustra.
In Mike Resnick's The Outpost, Magnificent Bastard Hurricane Smith, one of the galaxy's top bounty hunters, has this trope has his main passion in life. He's already had five ex/late-wives, all different alien species, as he finds human women to "all look the same". After he and his fellow bounty hunters help save the galactic human Democracy from a genocidal alien invasion, he is last seen in romantic pursuit of a sentient spaceship (with female A.I.), as he rebounds from the death-in-battle of his last wife, an insectoid shapeshifter.
In Piers Anthony's Cluster series, powerful Ancient structures are often activated by creatures with strong Kirlian auras having sex in or on them.
Citizens of The Culture are genofixed to be genetically compatible with most humanoid species. Their genitals are also modified for increased ability to sustain a climax, which leads to all sorts of rumours and envy among other civilizations. Having a dedicated gland for secreting all kinds of mind-altering substances for personal use also helps to get into the mood.
Averted by Star Trek: The Original Series. While Captain Kirk fell in love with a new person weekly, and there were quite a lot of interspecies kisses, the writers only made it clear he'd had sex on two occasions: once, a native wife became pregnant, and once the show returned from commercial to find a woman brushing her hair in his room while he put his boots back on. There are numerous examples of interspecies reproduction (Spock being the most famous example) throughout the franchise, however, so apparently quite a few individuals boldly came.
In the Star Trek: The Next Generation episode "First Contact", Commander Riker gets an offer to help him escape a hospital facility from a nurse in exchange for this.
Riker: "The things I do for Starfleet."
Riker again the episode A Matter of Honor. Participating in a officer exchange program, Riker signed on to a Klingon vessel, the crew of which subjects him to a rather unusual Secret Test: seeing how he reacts to two female shipmates openly flirting with him. He passes.
Klingon Officer: They want to know how you would endure. Riker: Endure what? Klingon Officer Them. (Riker gives the females an appraising look) Riker: One, or both?
A Star Trek: Voyager episode has Harry Kim falling for an alien babe and catching a disease (and no, it's not SpaceClap). Turns out there are Starfleet regulations that say you've got to clear this with your ship's doctor first. Given the popular view of Captain Kirk this led to fan accusations of Series Continuity Error, though it could easily be justified as the regulation having been made as a result of those Original Series crews shagging their way across the galaxy, filling it with Human Aliens.
Smallville. Technically when anyone had sex with Clark, Zod, or any other Kryptonians.
The Classic series had its examples of companions using time and space to shag various historical people and aliens, too - Barbara was (by Word of God) banging the Thal Alydon offscreen in "The Daleks", and a possible reading of the scene at the end of "The Massacre" where Steven theorises that Dodo is a descendent of Anne Chaplet is that he's also theorising that he is one of her ancestors...
It has this in the series finale. Upon finding human natives on the planet Kara led them to, the first thing Gaius Baltar talks about is their genetic compatibility with the Colonials. Adama does not let this go without a Lampshade Hanging at Baltar's expense.
Speaking of Battlestar Galactica, are there any characters on that show that didn't boldly come? Gaius did anything with a vagina and a pulse, Chief Tyrol married Callie, Helo nailed Boomer, the guy that Starbuck married eventually turned out to be a Cylon, Tigh's wife was sometimes accused of being a slut... hell, even Admiral Cain (!) got some robot Girls Love in Razor.
John Sheppard is rather prone to this, usually followed by collective eye-rolling by the rest of the characters. In the episode "Sanctuary", Rodney accuses him of "the Captain Kirk routine" of "romancing the alien priestess", and calls it "very 1967".
McKay (channelling his inner McCoy, no doubt): "Oh my God, he is Kirk."
Col. O'Neill: Daniel, you dog, you keep this up, you'll have a girl on every planet.
And the truly alien beings (Unas, Asgardians, etc) generally have as little interest in sex with humans as the humans do with them. Though given the nature of the show, most of the people are government officials, military, or otherwise high in status so any sort of hanky panky would have to be very discreet to avoid... problems.
An episode subverted this trope with Ivanova, who did not want to have sex with an alien diplomat whose species uses the act to finalize business negotiations. Because the alien actually had no idea how humans mated, she she managed to trick him into thinking that a firm handshake and a weird dance was the human way to do it.
The one who was Boldly Coming was G'Kar, who in the earlier seasons would have sex with anything that had compatible genitals (apparently including humans). He also slept with one of Londo's wives. Since humans and Centauri are more or less incompatible,note Centauri genitalia consist of six tentacles for the males emanating from the back and folded across the chest when not in use, and six corresponding slits for the female. Using all six is necessary for maximum pleasure/impregnation. As one might imagine, it's probably easier for a male Centauri to do the nasty with a human or human-compatible woman—or probably women—than the inverse. he apparently didn't feel limited by mere anatomical details. Technology is a wonderful thing.
A scene (originally deleted) from the pilot movie indicates that there are laws restricting with which species humans are permitted to have sex. Speciesist? Maybe. But there are reasons...
Commander Sinclair: I wouldn't. You know the rules about crossing species. Stick with the list. Man: What are you, a bigot or something? Sinclair: No. But obviously you've never met an Arnassian before. After they finish, they eat their mate.
The short-lived Babylon 5 sequel Crusade reveals that human-Pak'ma'ra porn exists. Also, certain creatures living in hyperspace may try to mate with passing starships. According to J. Michael Straczynski, one of the Executive Meddling demands for the series that he turned down was a demand for the introduction of a "sexual explorer" character whose official job would be this.
This is a large part of the Stephen Spielberg miniseries Taken, with the aliens breeding with humans to eventually create Ali.
In the backstory of Tracker-most recently, Mel's grandparents.
Averted (in the nick of time) during the sixth series of Red Dwarf when Lister is forced to marry a GELF in exchange for a part needed to repair their ship. While his new orangutan-like bride seems very eager to consummate their marriage Lister resists as best he can before escaping under the pretence of needing to 'slip into something more comfortable...it's called Starbug.'
While neither Rimmer or the Cat have actually done this, they both express interest in doing so; Cat (a humanoid evolved from a housecat) conjures up Marilyn Monroe (as well as a reverse mermaid with the fish part on top) to date in the Total Immersion Video Game. Rimmer fantasizes about meeting aliens, and is very intrigued at the possibility of females with more breasts than is the norm.
Kanye: Tell me what's next, alien sex / I'mma disrobe you, then I'mma probe you / See I abducted you / So I tell you what to do!
Heavily implied in the Star Trek Pinball table "To Boldly Go", where the playfield is dominated by a leering James Kirk surrounded by a half-dozen wary women.
The Coalition (a group of alien species) in Trinity are another reverse example, as their goal is the acquisition of fresh genetic material...including through sex. They rape the human first contact team to death, try to do the same to the group that comes to check what happened to said team and are later observed doing it to a native alien population on a planet they've just taken control of.
The d20 version plays it straighter, with sexual contact considered a normal method of interaction between species in the Coalition's home region of space. The human first contact team gets raped to death unintentionally, but second contact goes well, with no sexual interaction.
The Exotophilia, near-universal biological compatibility, and empathy of asari probably smoothed out first contact with the salarians to no end. And the turians, later. And the humans. And the krogan. And then, and then, and then.... In fact, inter-asari relationships producing children are discouraged and the children of such relationships are given the slur "purebloods." "Pureblood" asari have a small chance of turning out to be Ardat-Yakshi.
It's mentioned in flavor text for Tevura that asari have always been exogamous, traveling far from their origins to find mates in order to prevent inbreeding. This makes anti-pureblood sentiment and preference for nonasari look a lot like aversion to incest, and raises the question of whether Ardat-Yakshi parents tend to be related.
In the series as a whole, it's very easy to play Shepard as a Kirk expy. He or she can schtup turians, asari, drell and quarians. There are medical issues associated with all of these relationships, as Mordin is very adamant about pointing out, but for sex, you risk it.
Yeoman Kelly Chambers wholeheartedly endorses the boldly coming approach.
Even The Illusive Man, Human Supremacist Supreme, isn't exempt from this trope. Amongst the data the Shadow Broker keeps on him is a list of TIM's Sexual Liasons. There are a lot of human supermodels and an Asari Matriarch (twice). Averted in the case of his minion Kai Leng, who in the books finds all aliens physically repulsive and considers the Asari "whorish".
Grayson, one of the major protagonists of the Mass Effect book series, takes an asari lover in the third book and, after a particularly wild night with her, wonders how he would ever go back to humans. Also, keep in mind that this coming from a man who once actively hated aliens.
Tali also seems to have a touch of Xenophilia; she's a viable love interest for a male Shepard, and if you don't hook up with her, she'll eventually end up in a relationship with Garrus, and during the Citadel DLC she's willing to entertain the possibility of a threesome with herself, female!Shepard, and Garrus. She also notes that an in-universe movie called Fleet and Flotilla, about an inter-species romance between a quarian and a turian, "jumpstarted" her puberty.
The existence of the magazine Fornax, a publication dedicated to the finest in interspecies erotica, should tell you how this trope is faring in the Mas Effect universe.
Over the course of both games, the possible romances include four humans, one Cathar, one Miraluka, and one Echani. (Fandom will also include the Zabrak tech for females...) However, one of the humans in the first game is the only pairing in which sex is confirmed to occur, the Echani looks just like a human (and is half-human anyway), the Miraluka is a human with no eyes.
Miraluka and Echani are stated to be "near human," close enough to human for mating to work, but there are some genetic and culture differences due to thousands of years of adapting to their native worlds. The Cathar is a Gay Option, and definitely not in the near-human bracket.
In the backstory, the Furons arrived on Earth thousands of years ago and did this with the humans, to the point where nowadays, every human being on Earth has some Furon DNA. Later, the Furons return to Earth to harvest the pure, uncontaminated DNA from the humans in order to save their species from radiation-induced sterility.
Crypto also does this with Natalya at the end of the second game as well as heavily suggested as doing this with an assortment of random women ever since getting his genitalia back.
Male Sims (and likewise female Sims) can woohoo with aliens of either sex in their neighborhoods or homes.
Also, if an adult male Sim gets abducted while looking into the expensive telescope, he comes back traumatized and pregnant. (Female Sims may come back traumatized, but almost never pregnant. Usually to get a female Sim to have an alien baby, she either has to woohoo with a male alien in her neighborhood (or home if he lives with/is married to her), or visit the Tombstone of Life and Death and choose " make me alien pregnant" from the pie menu.)
In the sixth game Sophia mentions in a support conversation that her mother was a dragon. It's possible that Roy is actually a quarter dragon because his mom could have been Ninian. However, it's left very ambiguous as his mother could also be Lyndis or Fiora.
In Hasha no Tsurugi, the manga adaptation of Fire Emblem 6 , Al is the child of the human leader of the Eight Divine Generals (Hartmut the Hero) and a female Ice Dragon.
In the seventh game Ninian and Nils were the children of a female ice dragon and a human druid.
The half-dragon receives his non-human blood from his mother. Aside from Soren, the only other branded to have his precise parentage confirmed is the unnamed first branded, who plays this straight.
Exaggerated in "Fire Emblem Awakening" as the Manakete Nowi and the Taguel Panne are the mothers of the half-Manakete Nah and the half-Taguel Yarne, respectively speaking — and all the possible fathers are human men, as there are no good male Manaketes and Panne is the last full-blooded Taguel. Either of them can potentially be the mother of a female Morgan via marrying the male Avatar, too.
John the troll from Fairy Dust loved women from most fantasy races available. He counts on them finding him exotic.
In Loon Land the alien Lana Loon lands on earth and has a close (failed sexual) encounter with the terrestrial loon Mike Moon .
Mike: Hang on! You've got like five holes down here! Which do I poke it in?
Lana: All of them.
Three Worlds Collide features a First Contact scenario between humans and two other sentient spacefaring species simultaneously. One of these, dubbed "Super Happies", takes this trope and runs with it - all their communication, both among themselves and with other species, is based around having sex.
More than that. Their communication IS having sex - it seems that evolution decided that, while one transfers genetic information, all sorts of other information might be traded as well.
Inverted and played straight in a 365 Tommorows story. In this case, the ones having carefree sex are the Sybaris, the alien species that the humans came into contact with. It's played straight by the human delegation to the Sybaris.
Zapp Brannigan aspires to do this, but is just so bad at it.
Zapp: We have failed to uphold Brannigan's Law. However, I did make it with a hot alien babe. And in the end, is that not what man has dreamt of since first he looked up at the stars? ... Kif, I'm asking you a question.
Oh, and the hot alien babe was actually just a mutant human.
Ironic of him to ask Kif that question, since Kif also ended up making it with a hot, alien babe, namely Amy Wong. Which means she filled this trope, too. And so did Leela, when she got Kif pregnant (accidentally; don't ask). In fact, Zapp is the only one of the four who hasn't, despite having built his whole life around trying.
If Amazonian women are alien and not just giant humans, then Zapp did make it with a significant number of hot alien babes.
Zapp: Ladies, please, the spirit is willing but the flesh is spongy and bruised.
Lrrr, Ruler of the Planet Omicron Perseii VII, did this accidentally after separating from his wife Ndnd and going through a mid-life crisis. He hooks up with what he takes to be a hot Omicronian woman, but afterwards learns that she was a human in costume (it seems some humans are into this sort of thing), and she thought he was actually a human as well. Lrrr is horrified that he slept with a human, but the girl is still into it.
Maxwell Tennyson aka "Grandpa Max" from the Ben 10 series has dated at least one literal green-skinned space babe and later married an Energy Being who is also the mother of his sons and Ben's grandmother.