A little six-year-old boy is sitting on the toilet. His mother thinks he has been in there too long, so she goes in to see what's up.
The small boy is seated on the toilet, engrossed in a book. However, approximately every ten seconds, he sets the book aside, grasps the toilet seat with his left hand, and gently taps himself on the top of his head with his right hand. 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.
Mother says, “ Okay, you can stay here a few more minutes. But, Billy, why are you hitting yourself on the head?"
Billy says, “ Works for ketchup."