The Farmer
A farmer and his wife are lying in bed one night when the farmer starts to rub her breasts. He says "If these would only give milk, then we could get rid of our cows."
After a few minutes he starts rubbing her bottom. He says "If this would only lay eggs, then we could get rid of our chickens."
After a while his wife starts rubbing his penis. She says "If this would only get hard more often then we could get rid of the farmhand!"