The act of being a worthless, annoying, prick who is slightly nerdy and/or dorkish.
Dude1: Hey man did you hear that jacob is dating Katy.
Dude2: Yeah he's a Nipple Fart
when your nipple produces a high pitched , highly embarrasing squeak
oh shit! a nipple fart right in public , OH GOD STOP STARING AT ME!