Double Subverted: ... named Alex, who is in fact her counterpart in that dimension.
Bob goes into a parallel dimension, takes a USB filled with porn with him, and exchanges porn stashes with his different dimension counterpart. Also a downplaying.
Alice goes on a raping spree exclusively targeting her alternate dimension counterparts. The inter-dimensional court is unable to convict her, since what one does to oneself is nobody's business.
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.
"So how'd you like meeting yourself?" "Oh, I'd say we got on pretty well..."
"That's, like, inbreeding ratcheted up to eleven! Aren't you worried you're gonna give birth to some kind of horribly deformed clone baby?"
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.
Alice hits on her counterpart. They aren't keen on the idea.
Alice's parallel dimension counterpart hits on her. She isn't keen on the idea.
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.