The Potty

A little three 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 little boy is sitting on the toilet reading a book. But about every 10 seconds or so he puts the book down, grips onto the toilet seat with his left hand and hits 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, "OK, you can stay here for a few more minutes. But, Billy, what are you hitting yourself on the head?"

Billy replied, "It works for ketchup!"