I'm looking for a Weecest fuck-or-die fic. From what I can remember, Sam, Dean, and John are all trapped in a motel room and can't leave until Sam and Dean have sex. They're pretty reluctant at first and Dean winds up bottoming but after a bit it winds up being pleasurable.
The story is from John's POV, and the whole thing is really awkward for him (obviously). The story itself is really lighthearted though, all things considered.