The process of, while penetrating a partner from behind (Either anally or vaginally), reaching around and playing with his/her genitalia.
Contrary to popular belief, not only a homosexual act.

When your partner gives you a handjob from behind.

That service one provides while fucking you up the ass.

The act during a MMF threesome in which a man reaches around another man in a Mitchell-like maneuver and grabs the other man's penis.

1. A total idiot. A tool.
2. A sexual maneuver

a homesexual activity in which the person doing them gives them a handjob

A game that wich only man can play. Where you throw a ball is throw'in behind your back to another person. Quit like the flow of atoms.