sphincter slam 

A sexual manovere in which sum 1 proceeds to jump and land on there front will giving sumone a buttfuck

Jim gave micheal a huge sphincter slam.
There was blood every where

sphincter slam by Lucas December 31, 2003

Sphincter slam 

When you fart so loudly both your butt cheeks close simultaneously

Most of the night you want to go to the bathroom & do a sphincter slam but you don't for fear it'll wake up the neighborhood

Sphincter slam by Faithmoriahfaith June 22, 2015