When you have a retarded penis. When youre actually retarded enough to have a penis with a brain of its own. Wtf? If you have a penizzle then Steven Nipper will come slap it so watch out. Penizzles are usually shaped like a pretzel, therefor making it "interesting" to give head to.
Joe lookoed down one day only to notice that he had a penizzle. What a fuckin niglet. Therefor steven went and slapped it.