Dirty mudflap 

When you pass a wet fart on someones tongue as they are licking your anus.

I had mexican food last night and I accidently gave Mindy a dirty mudflap.

Dirty mudflap by Freakshow 1975 September 11, 2006

dirty mudflaps 

A righteous ba donka donk butt, the kind you'd just wanna stink your face in between and go BRRRRRRZANG

yobags, did you check the dirty mudflaps on that one?

dirty mudflaps by Jon Himself March 13, 2003