The way I heard it: An Englishman is giving a Scotsman a ride home from the pub. The car rounds a corner and the headlights reveal a sheep stuck in the fence. "Stop the car! Stop the car!" yells the Scot. He jumps out, enjoys some ovine pleasure, comes back to the car. "Right, your turn," says he to the driver. The English fellow gets out, walks over, and sticks his head in the fence.