A small patch of hair on a mans chin. Not exactly a goatee because it's not connected to a mustache, but bigger than a soul patch. Commonly used in a derogatory manner.
When fucking a giraffe in the ass, the small tuft of hair on the end of its tail is used to gently tickle the scrotum for pleasure.
Small child:Mommy what's that dirty dirty man doing to that adolescent giraffe?
Mom:Oh don't look honey, it's just the nut duster, you'll understand when you're older.