There's a farmer, and one day his truck breaks down. He doesn't have any money to pay the mechanic to fix the truck, and he doesn't have any other reliable transportation. His only other means of transportation is an old donkey, which has a rather peculiar habit: sometimes it will just stop in the middle of the road. The farmer has found through experience that when the donkey does this, the only way to get it to go again is to scratch it.
The farmer comes up with a plan. He'll ride the donkey into town, and take a chicken and a rooster with him to sell at market. Then he'll be able to pay the mechanic to fix the truck.
So, he gets on the back of the donkey, rooster in one hand, chicken in the other, and starts to ride toward town. It's about five miles away. Halfway there, the donkey stops! The farmer finds that he cannot scratch it, because his hands are full. If he lets go of either bird, it will fly away.
While he's sitting there pondering his next move, another man comes down the road in the other direction. The farmer calls down to him, "Hey buddy, do me a favor, would you? Hold my c*ck and pullet while I scratch my ass."

Tom, Tom, Tom,..