Playing With / Screw Yourself

Basic Trope: Somebody has sex with a duplicate of themselves.
  • Straight: Through Time Travel, Alternate Universe, cloning, magic, or some other form of plot device, Alice mets another Alice and has sex with her.
  • Exaggerated:
    • Alice has Three-Way Sex with two other Alices.
    • Alice has a long-lasting relationship with her counterpart, and even has a kid.
  • Downplayed:
  • Justified:
  • Inverted:
    • Alice has sex Bob, and HIS other self.
    • Alice has a lot of self-loathing, so vigorously hates her alternate self and tries to kill her.
  • Subverted: Alice seems to be in bed with herself, but it turns out to just be her identical twin, Carol.
  • Double Subverted: … but then we find out that Carol actually is Alice's other self, brought back for another dimension. Here, Alice just calls her other self Carol and says she's her twin to avoid lengthy explanations.
  • Parodied: Alice creates all kind of clones of herself, from loli-type to Onee-sama-type to Bifauxnen-type to Bastard Girlfriend-type (etc), just to have fifty shades of her own flavor.
  • Zig Zagged: Alice goes into a parallel dimension, and meets someone offscreen. (S)he takes her to their place... which happens to have the same address as her house in her own dimension. The next morning, she is shown leaving and being kissed goodbye by a man. He is called Alex, and has had gender reassignment surgery. He looks nothing like her. His hair is dyed, and if it wasn't he would look suspiciously like her.
  • Averted: Nobody travels between dimensions, or considers sexual relations with an alternate version of themselves.
  • Enforced:
  • Lampshaded: A time travel agency warns its customers that your other selves may have STDs that your present self does not.
  • Invoked: Alice builds and uses a machine to travel to a parallel dimension for this explicit purpose.
  • Exploited: Alice whores herself to her alternate dimension counterparts, because she wants things they have which she don't. And they are divergent enough that she can rely on this method to solve each and every one of her problems.
  • Defied:
  • Discussed: "Try not to meet yourself when you go back in time." "Why? Worried that I'll fall in love with myself?"
  • Conversed: "So does that make Alice a narcissist or something?" "Nope, it makes her smart. Who knows your way around your body better than you yourself? If I had that opportunity, I wouldn't miss it."
  • Implied: Alice travels to another dimension. She goes off on her own for a little, then returns Sex Dressed. Bob asks what happened, and Alice says, "I think I just met my other self." There is no further explanation.
  • Deconstructed:
  • Reconstructed: When her interdimensional transporter is destroyed, Alice puts all her time and effort into repairing it so she can resume her relationship with herself, while occasionally enjoying A Date with Rosie Palms and wishing it was her other self. Their reunion is a Crowning Moment of Heartwarming... and much more.
  • Plotted A Good Waste: "Damn, me-on-me action is hot, I'm so awesome and so am I." said our-dimension Alice with a wide smile on her face as she lies next to herself.
  • Played For Laughs: The two Alices look each other in the eye, run into each other's arms, and passionately kiss. They break apart simultaneously and ask each other in unison, "Am I really such a horny desperado?" Then break out in unified laughter and go right ahead. Coitus Ensues.
  • Played For Drama:
    • Alice's parallel dimension counterpart is a man. They have sex. Alice gets pregnant, and everyone wonders to whom. To make matters worse, when it's born everyone wants to know why the female child looks exactly like Alice. And she has to explain to them. As well as the child later in its life.
    • Alice has a serious self-esteem issues, and is a huge jerk to boot. One thing and another lead to her meeting her alternate-dimension counterpart, which is the only one in the entire multiverse who will say "But Your Wings Are Beautiful" (and vice versa). They eventually get over their self-esteem issues together, and the story ends with their marriage. The whole thing plays like a cliched romance novel.

"And you, Miss Alice, can go back to Screwing Yourself!"
http://tvtropes.org/pmwiki/pmwiki.php/PlayingWith/ScrewYourself