A man walks into a bar and sees a sign that says, "Free drinks for life to anyone who can make our horse laugh."
The man thinks to himself, "I've got nothing to lose," and decides to give it a try. He walks up to the horse and whispers something in its ear. Suddenly, the horse starts laughing hysterically and the bartender is amazed.
The man drinks for free that night and comes back the next day to try again. This time, he whispers something else in the horse's ear and once again, the horse can't control its laughter.
This goes on for weeks and the man is drinking for free every night. Finally, the bartender asks the man, "Okay, you've won free drinks for life, but I have to know what you're saying to make that horse laugh so much."
The man looks at the bartender and says, "Well, the first time I told him my dick is bigger than his. The second time, I showed him."