Junk Trunking
The act of having anal sex for so long your balls penetrate as well.
Man 1: Man my dude my balls are sore.
Man 2:Why?
Man 1: Cause I was fucking a chick in the ass and I then my balls slipped in.
Man 2: A JUNK TRUNK?! MY MAN! YOU JUNK TRUNKING SON OF A BITCH!!