1 definition by Bryan Z.
When you're having sex with a fat person, you slide your penis inbetween their folds of fat until you climax into the belly button.
Person A: "You had sex with someone THAT fat?!"
Person B: "Yeah! It gave me the chance to do a Matt Nasty!"
Person B: "Yeah! It gave me the chance to do a Matt Nasty!"
by Bryan Z. July 28, 2006