Here's one... feel free to add yours. Originally from Jackie Martling, former Howard Stern sidekick and stand up comedian. Two kids are playing doctor. Johnnie takes off his pants, and Mary looks down and says "what's that???" "I dunno" the he answers, "but I know my dad has one too, I will ask him." That night dad is taking a shower, and the boy opens to curtain, points to dad's junk and says "Dad, what's that." Dad answers "Son, that is a penis. In fact, that is a PERFECT penis." The next day the Johnnie sees the girl again, and again they play doctor. His pants come off and Mary says "did you find out what that is?" "That is a penis," Johnnie says. "In fact, if it was three inches shorter, it would be a perfect penis."