A large, ugly pimple that develops on the ass if you haven't been washing for a while. It doesn't hunt, but will otherwise annoy until finally popped (usually with fire). If you don't continue to wash, it'll come back in six weeks.
Person 1: Dude, my ass is annoying the fuck outta me.
Person 2: I think you got an MNG on your ass. You should pop that shit and start washing your ass, you greasy motherfucker.
Person 2: I think you got an MNG on your ass. You should pop that shit and start washing your ass, you greasy motherfucker.
by Everyday Common Sense February 20, 2011
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