Finn and Poe are trapped in a tight space together for several hours and they have to keep quiet (hiding, stowaways on an enemy ship, w/e) Except Poe really needs to pee and of course the urge keeps getting progressively worse. Turns out Finn has an... interest. And it doesn't help at all that Poe keeps squirming against him, clearly desperate but trying to keep still and quiet and not blow their cover.

Would love it if there's some h/c in there where Finn's main concern is to try and soothe Poe a little and he won't act on his arousal if Poe's uncomfortable with that. (Totally up to author if he is though, I'm always down for things unexpectedly turning into porn :D)