Skunking is an ability that Skunk has. Being a skunk, whenever he is frightened, angry, or surprised he will accidentally spray a noxious gas out of his rear. Such gas is able to knock out any opponent with its bad smell, just like skunks regularly do. While powerful, it is a great embarrassment for Skunk who cannot control it. But whether he, or anyone else, likes it or not Skunk will have to master this unusual power and use it against Dragon.
In The Art of the Crush, it's almost used in embarassment against Fox after she defeats Skunk in a sparring match by pinning him. Near the ending she uses it again, but to her advantage by pinning Skunk again and kissing him on the nose.