Definitions by Spellbound

cock sisters 

two girls who have slept with the same guy

"hey girl, you know, we cock sisters. I was with that fool years ago, before you ended up with him."

cock sisters by Spellbound July 3, 2014

vag brothers 

two guys who have slept with the same girl

"Dude, we're vag brothers. I was tapping that before you where."

vag brothers by Spellbound July 2, 2014