7 10 Split
When you're going at a girl from behind, you spread her legs and you put your balls in her pussy and then fuck her in the ass. If you punch her in the back of the head right as you cum, it's called picking up the spare.
Guy 1: "Dude, Kay was actin' a fool last night so I gave her the old 7 10 split."
Guy 2: "Did you pick up the spare on that shit?"
Guy 1: "You know it, bro!"