This is half-formed. Sue me! If you're up for hashing through an idea into a plot, PM me!
Anyways, I'd really like to do something that poked at power dynamics. Specifically, the idea of one character being annoyed at the developing sexual relationship is a turn on. Maybe the guy is kind of a jerk. I don't know. The idea is being in something you know you shouldn't be, but not having the ability, in the heat of the moment, to pull out.
Not n-con. Definitely consensual, just the sort of consensual that makes you say "fuck, again!?" and have a drink.