A farmer is giving his blonde wife last-minute instructions before heading to town to do chores.
"That fellow from the University 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 blonde wife understood the instructions, 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 tells him.
"What's the nail for?" the guy asks.
Replies the wife, "I guess its to hang up your pants."