Funny Dirty Joke

A guy walks into a bar, and sees 50 bucks on the counter, and asks what its for. A guy walks up yo him and said, "If you can make my donkey laugh I'll give you this money. Leaves the room and comes back, and the donkey is cracking up, he takes the money then leaves. Comes back the next day and sees 100 bucks on the counter, the guy said if you can make my donkey laugh I'll give you this money. He leaves the room and comes back and the donkeys balling. How did you do this? The guy replies "well yesterday I told him my dick was bigger then his and today I proved it." -takes the money and leaves-