A Sister Trope to Ladykiller in Love, this is what happens when The Casanova and the Femme Fatale (Or some similar character archetypes) are both trying to seduce each other for their own purposes at the same time. Most of the time, there is no sincere romance between the two, each one is strategically putting the moves on the other, trying to seduce them to join their side, give them information, or obtain the MacGuffin for them. As such, this is often one of the Espionage Tropes. Often, a Duel of Seduction ends in a Sex–Face Turn. In the meantime, it's a good opportunity for copious Fanservice.
There is a bit of a Double Standard with this trope. Because a woman with a lot of sexual experience and drive is a lot less socially accepted than a man with the same, more often than not the seducer is on the side of good, and the seductress on the side of evil. The seducer is more likely to convert the seductress to his side in the end, and she often loses much of her power and appeal in the process because Good Is Dumb.
- Kaguya-sama: Love Is War crosses this with Battle of Wits. Kaguya and Shirogane are in love with each other, but a combination of pride, shyness, and insecurity keeps both of them from confessing. So they both try to force the other into a situation where they'd be forced to admit they're in love. Hilarity Ensues.
- This eventually ends with Kaguya finally asking out Shirogane over winter break a week after their First Kiss, though it was merely a formality at that point since both of them had ceased to care about "winning".
- Maken-ki!: Love Espada ends up facing off against Red "Desire", essentially a succubus version of herself, during chapters 111 - 113. Each tries to force the other to submit, via orgasm, using any and all manner of seduction and foreplay.
- Alluded to in Yuri!!! on Ice: Yuri, for a figure skating performance on the theme of "Eros" (sexual love), imagines the story of a Casanova who comes to town to seduce the most beautiful woman there. Since Yuri cannot empathize with the womanizer, he gives the story a twist—the beautiful lady turns the tables on the Casanova and seduces him—and Yuri then plays the woman's part in his figure skating performance.
- Wonder Woman (1942):
- Steve Trevor had been working on seducing Dolly Dancer, a Nazi spy who was dating him to get information and didn't realize he knew who she was before he'd ever met Diana. Dolly tries to keep Steve alive when her superiors' plans finally come to fruition and manages to escape Diana in the ensuing chaos.
- Steve and Draska try to get each other to lower their guard with flirtations, the problem being that Steve is there on orders even though Draska knows exactly what he's doing and who he works for. This means the flirtations are entirely a smokescreen of courtesy and she holds all the cards, which Steve realizes but can't do anything about.
- A Brighter Dark: A relatively low-stakes but no less interesting example occurs when Solei and Laslow meet for the first time. It starts with him trying to invite her out to a night of tea, and then somehow spirals into an argument over who is superior in their skill of enrapturing the heart of their targets; him citing his longer lifespan and thus longer experience, and her citing her overall superior skill. It ends with her eventually deciding to prove her point by seducing him on the spot. After a rather...intimate speech, he quickly has to concede that she is clearly the expert of her field.
- Takes on another interesting layer with the strong hint that he might be her father...
- The Dangerverse has a variant. When Amanda Smythe and Luna Lovegood realize that they are both in love with Draco Black (and that he has feelings for both of them), they decide to make a formal contest out of it. Each of them gets two months to seduce Draco while the other steps back, and they repeat the cycle until he picks one or the other of them.
- Pirates of the Caribbean:
- The scene in Pirates of the Caribbean: Dead Man's Chest with Elizabeth Swan and Captain Jack Sparrow, each trying to get the other to do something in return for something else. She wants to prove he's not as bad as he pretends, he...well, his motivations seem transparent, but on the other hand, it's Jack.
- Jack and Angelica in Pirates of the Caribbean: On Stranger Tides.
- James Bond obviously is a good candidate for this. The most memorable scene has to be Thunderball with Fiona Volpe. It's notable for both failing to significantly affect the other's disposition.
- The10th Victim is a movie about citizens engaging in a Deadly Game where one contestant hunts the other. While this sort of thing isn't required, it is indeed encouraged, seeing as the game is televised. The seductress here - played by Ursula Andress - attempts it, but falls in love with her intended victim.
- Frank Herbert's Heretics of Dune. Murbella tries to use an Honored Matre technique to seduce and mind control Duncan Idaho's ghola, but his secret Tleilaxu conditioning allows him to seduce and condition her instead.
- They actually manage to condition each other.
- In The Demon Princes final volume, Alice Wroke is under orders from the villain to seduce the hero. He, being several steps ahead of the game, obligingly plays along. Although he doesn't sleep with her.
- Implied to have happened in two of the Lord Darcy stories. In one, a female spy zaps Lord Darcy with an infatuation spell. Darcy realizes what happened, and spends the night letting her get false information out of him.
- In the Wings Quartet, Tamani seduces Yuki, a spy for troll hunter Klea, in order to get her to give information on Klea's whereabouts. It is revealed that Yuki is a faerie and knew that Tamani was one as well. However, she did eventually develop real feelings for him.
- Elsabeth Soesten is hired to recover incriminating documents from Lord Cuncz, the Baron of Leyen. She decides the best means of gaining access to them is to seduce the Baron. And then she learns Cuncz was the one who hired her in the first place, and that he was seducing her by letting her think she was seducing him (and her own plan was built on pretending to fall for his seduction attempt). It didn't even have anything to do with his own plans; he did it entirely because he wanted to bed her.
- In the Urban Fantasy Red Room series, succubus Shannon O'Reilly and seduction-trained agent Derek Hawthorne use their formidable skills on each other to get an advantage while being forced to team up. They fall in love instead.
- In Jason Matthews's Red Sparrow, Russian SVR seductress Dominika Egorova is tasked to seduce CIA agent Nate Nash for information on a mole within the SVR. Nate had just been kicked out of Moscow and was just looking to get his career back on track in Helsinki when he stumbles on Dominika. Throughout their interaction, it's only Dominika who tries to seduce; Nate was only looking to recruit her as an asset. Yet they enter into a relationship anyway.
- In Thin Air by Richard K. Morgan, freelance overrider Hakan Veil and Earth Oversight auditor Madison Madekwe engage in a Duel of Seduction in order to influence the ongoing political and economic conflict between Earth and Mars. Due to the Double Standard, Veil's allies assume that he alone is being seduced and Veil helpfully lampshades this trope for them to get them to stop warning him off.
- Played for Laughs in the Friends episode "The One Where Everybody Finds Out". Rachel and Phoebe have just found out about Monica and Chandler's secret relationship. Phoebe flirts with Chandler to mess with them, but Monica and Chandler find out and get back at them by playing along. Chandler invites Phoebe over to have sex and they each try to scare the other person away with their advances, with Monica encouraging Chandler and Rachel encouraging Phoebe. It becomes very awkward since they are both repulsed by the idea.
Chandler: [in fake enthusiasm] I'm so glad we're going to have all the sex!
Phoebe: You should be. I'm very bendy!
- Star Trek: The Original Series
- "The Enterprise Incident". The seductress is a Romulan Commander Worthy Opponent, and oddly enough, the seducer is not Kirk, but rather Spock.
- In "Wink of an Eye", Captain Kirk romances Deela to delay her Evil Plan and get his hands on her weapon. Deela is fully aware of this and quite amused. She in turn is trying to seduce Kirk so he will become more accepting of his situation.
- Gossip Girl - Chuck and Blair, nearly all the time. Subverted as they do in fact actually love each other but are just incapable of admitting it to each other and are/were in fact, the most popular pairing on the show. Blair is also not portrayed negatively or evilly.
- In Firefly, a good one between Inara and Saffron. Both recognize what is going on, as they've both had the same training as high-class courtesans.
Inara: I guess we've done enough lying.
Saffron: You're good.
Inara: You're amazing; Who Are You??
Saffron: Malcolm Reynolds's widow.
- Annie Walker and Simon Fischer for several episodes of Covert Affairs.
- Played for Laughs in an episode of Chuck. Spy couple Chuck and Sarah are both trying to seduce each other. Over their wedding plans. Hilarity Ensues when they both realize what the other is up to. And it gives five minutes of Sarah in a Belly Dancer outfit.
- In the short-lived Australian historical sitcom Bligh, a Senior Cassanova is running a quiz competition between Governor Bligh and his Sitcom Arch-Nemesis John Macarthur, who both send their wives to seduce him and steal the answers. They always seem to forget the second part of the plan.
- The White Stripes song "Conquest": 
- Dungeons & Dragons:
- An ancient in-game joke: Once Upon a Time a young lad and a young lass, wizards' apprentices. They decided to exchange some magics. Both cheated and cast Charm Person to ease the bargain, and both failed their saving throws horribly. They lived Happily Ever After and even died the same day.
- One source describes two very unlikely lovers, the agathinon Janarr and the erinyes Nalura hiding out in mortal disguise on the Prime. They sort of just did their jobs too well; she tried to seduce him, he tried to turn her attitude up to celestial standards. Before they knew whom exactly they faced, both succeeded. They had to hide from their respective bosses from that point on, though.
- This is one of the many, many ways Maids can compete for Master's love in Maid RPG. They can do this with each other as the target of seduction.
- Knights of the Old Republic plays the hell out of this one in the trial scene on Manaan. It starts as a straight-up version of this, then gets interesting.
- An interesting version (with Psychic Powers) turns up as Samara's loyalty mission in Mass Effect 2. Shepard is required to catch the attention of Samara's daughter, Morinth, who kills people by sleeping with them. This requires three steps: first draw her attention by making a scene in her favorite bar (punch people, stare down a krogan, dance really well), then pique her interest in conversation, and then she takes Shep back to her apartment and tries to turn her telepathic abilities against the commander, who tries to resist through sheer virtue and/or badassery. It's possible to blow either the second part (in which case she walks out and you fail the mission) or the third ( she draws Shep under her spell and is about to strike when Samara blows the door in). Oh, and Morinth is an asari, so Shepards of either gender can participate.
- Played With in Sandra on the Rocks. The ex-married couple and professional rivals Domenico and Zoé try to settle a dispute involving their protegé Sandra which quickly devolves into them having Sex with the Ex while a confused Sandra hears the Destructo-Nookie action from outside the bedroom. Tatiana explains to Sandra that this is their usual way of settling arguments, getting into a competition where they attempt to "sex each other into submission". Zoé emerges victorious and doesn't ever bother putting her clothes back on as she's too eager to leave and "wash the stench of ex-husband off her body".