Rocking Chair Rumble

An elderly man and woman are rocking on the porch one evening, enjoying the sunset. Suddenly, the woman gives the man a sharp crack across the head, knocking him to the floor.

"What was that for?" he asks.

"For having such a small penis," she says, and continues to rock.

The elderly man gets up from the floor, calmly walks over to his wife, grabs her rocker by the handles and flips her on to her back.

"What was that for?" she asks.

"That's for knowing the difference!"