Gene Juan LaFlair's definitions
A belly buster is a dude who, when masturbating, will prefer to ejaculate onto his stomach (or belly) rather than into a Kleenex or tissue paper.
So-and-so is a belly buster because he jerks off while lying on his back in bed and "busts his load" onto his belly, with the hope that he will not hit himself in the face.
by Gene Juan LaFlair September 27, 2009
Get the Belly Bustermug.