When a man farts while sitting on a nonporous (usually leather) seat and the gas expanding from his anus rapidly pushes his nuts forward, approximating the behavior of a pneumatic piston or cannon. Frequently catalyzed by the presence of tight pants and/or sweaty ass/thighs.
Dude, it was so hot this morning I was cannonballing all the way to work in the old Caddy. Gotta get me some cloth seats, or stop eating fuckin' breakfast burritos.
by Bendy May 15, 2006
by bendy September 03, 2003