A guy goes to a doctor with a spot on his forehead. The doctor says "Amazing, I've only read about this in the journals! In a few weeks, you'll have a penis growing out of your forehead."
The man says "Cut it out, doctor, help me!"
The doctor says "Nothing we can do, it's actually part of your brain and if we cut it out, you'll die. Sorry."
The man says "You mean to tell me, doctor, that in a couple months, every time I look in the mirror I'll see a penis growing out of my forehead?"
The doctor says brightly "Oh, no, no. You don't have to worry at about that at all! The balls will cover your eyes."
(Stolen from Al Franken who heard it from Buddy Hackett.)