The "penguin"

A guy who's strapped for cash asks a prostitute what he can get for $10. She replies, "Well, for 10 bucks I'll give you a 'penguin.'" "Okay... Sure, I'll take it."

So she gets down on her knees, lowers his pants, and begins giving him a blowjob. But right before he is about to cum, she gets up and walks away. The guy is confused, and starts to waddle after her, with his pants still around his ankles. "Wait, so this is a penguin?!?"

Got this from an old PlayBoy magazine.