A farmer is giving his wife last-minute instructions before heading to town to do chores:
“A guy will be along this afternoon to inseminate one of the cows.
I’ve hung a nail by the right stall so you’ll know which one I want him to impregnate.
“Satisfied that his wife had the instructions clear, the farmer leaves for town.
That afternoon, the inseminator arrives and the wife dutifully takes him out to the barn and directly to the stall with the nail.
“This is the cow right here,” she tell him.
“What’s the nail for?” “I guess it’s to hang up your pants.”