Reminds me of the farmer telling the city fellow about bricking a young bull.
The city fellow had no idea what he was talking about. The farmer explained that you quietly walk up behind the young bull with two bricks and whack them together at just the right place to produce a steer.
"Good lord, man!" replied the city fellow. "That must hurt awfully!
"Not at all, said the farmer, "unless you get your thumb caught between the bricks."