When you let out a fart that, while not loud or seemingly harmful, produces an extremely noxious odor similar to the smell of cat shit mixed with mothballs.
David crop dusted a group of girls that were seated in the Food Court at the mall. Although he figured it would smell, he did realize that he cut a Musty Waff until he turned around and all of the girls were gagging and choking.
by Eaton Holgoode June 19, 2009
Get the Musty Waffmug.