Little Johnny's Fire Truck

Little Johnny asks a fireman, "Do you want to see my fire truck?"

So the fireman goes to look at it. Little Johnny tested it. "I got my hat in my fire truck."

So the fireman says, "Last night's alright, but why is it tied up to you wagging?" And he looks closer and sees the string is tied up in knots. He said, "That's nice all right, but why is it tied up to his nuts?"

The little Johnny said, "Well that's my son," and so he yanks on it.