lewd adjacent, kink theory
I have this theory that a lot of kink is about associating things you’re not permitted to think about. Sex is the big thing you’re not supposed to think about or acknowledge (while simultaneously being the thing you’re supposed to want and be perfect at, in the approved form only). We already tend to associate nudity with sex, it’s a short hop away from all the processing about body image, valuation, punishment, competition, authority, all of the other unmentionables.