cross coitus
The act of two male roomates banging two females who are also roomates.
Bob: Hey Brett, Lizzy is coming over to add to my bucketful of pussy. I think Erin is coming with her.
Brett: Dude, we should totally ass to mouth the both of them and cross coitus in the same room.
Brett: Dude, we should totally ass to mouth the both of them and cross coitus in the same room.