1- What constitutes "beginning" to have sex.
2- Were you in the same room? Or was is something you did fritter away the lonely hours (minutes?) before your roommate returned from his erotic adventures?
3- Was this service requested? Part of the lease agreement?
4- If you were in the same room, did you try to "score" the scene as if it was a movie? Did you increase/decrease the tempo as they did? Or were you trying to direct the action through your music choices?
5- Was it ever reciprocated?