A juicy gurgling, squirtling, greasy fart, the kind you need to check your drawers after releasing, to make sure it was ONLY a fart. The sound of this type of fart is similar to an octave on a trombone.
the blood of a duck; or also the smell of a duck that you usually get on your person from duck hunting for several hours. also when you nail a duck and he goes down on the first gunshot. per Jacob
Man you got duck mustard all over you.
You mustard his azz.