Impulses.

Some people have a thing for fic about sibcest or fucking against walls. SPN fandom has a thing for knotting (no, don't google that. Seriously, I'm not joking.)

I have a thing for fic about really, really, really awkward sex.

( Cap/Bucky. Ish. Movieverse. Pretend this happens after Bucky and Steve talk in the pub, and Peggy leaves. Strong R. )