Milk Sisters
When two gay guys have had intercourse with the same guy, they become "milk sisters''.
Guy #1: I went home with a guy from the bar last night.
Guy #2: Ooh guuurl you slut. Was he cute? What's his name?
Guy #1: You know it! His name's Johnny.
Guy #2: Is he blond? Johnny... Johnny Smith?
Guy #1: Yeah....
Guy #2: Gimme a hug guuurll. We are official milk sisters.