I remember reading this Hotch/Reid fic about them having sex on the jet. The team walks in on them and they can just about hide what they have been doing but Hotch stays in Reid for the duration of the flight.
I have a strong suspicion that it was a fill in a kink meme because there were some comments discussing the scenario and one user mentioned Gideon would possibly act like the father in American Pie (?).
I just browsed through the memes but couldn't find it. Please let me know if you have a lead!