A little three year old boy is sitting on the toilet. His mother things he has been in the bathroom a little too long so she goes to check on him. The little boy is sitting on the toilet reading a book and about every 10 seconds or so, he puts the book down, grips the toilet seat with his left hand and hits his head with his right.
His mother says: "Billy, are you all right? You've been in here for a while."
Billy says: "I'm fine, Mommy. I just haven't gone 'doody' yet."
His mother says: "Okay, you can stay here a few more minutes, but Billy, why are you hitting yourself on the head?"
Billy says: "It works for ketchup."