My Name Is Mud
A big, fat farmer is walking down a dirt road in the rain with his big, fat wife when he suddenly gets horny. He pulls his wife down to the ground, lifts up her dress, and starts fucking her.
After a minute, he says, "Elsie, is it in you, or is it in the mud?" She says, "It's in the mud."
He reaches down, and fiddles around a bit. Then he says, "Now is it in you, or is it in the mud?" She says, "It's in me."
He says, "Put it back in the mud."