Young Johnny has a cursing problem, and his father's getting tired of it. He decides to ask a shrink what to do.
The shrink says, "Negative reinforcement. Since Christmas is coming up, ask Johnny what he wants from Santa. If he curses while he tells you his wish list, leave a pile of dog poop in place of each gift he requests." Two days before Christmas, Johnny's father asks him what he wants for Christmas. "I want a damn teddy bear lying beside me when I wake up. When I go downstairs, I want to see a damn train going around the damn tree. And when I go outside, I want to see a damn bike leaning up against the damn garage."
On Christmas morning, Johnny wakes up and walks into a pile of dog poop. Confused, he walks downstairs and sees another pile under the tree. He walks outside, looks at a huge pile of dog poo by the garage, and walks inside. His dad smiles and asks, "What did Santa bring you this year?" Johnny replies, "I think I got a damn dog, but I can't find the son of a bitch!"