The Blonde Is on the Other Foot.

A man goes to a supermarket and notices a beautiful blonde who waves at him and says "hello". He's rather surprised, because he can't place where he met her.

So he says "Do you know me?".

To which she replies "I think you're the father of one of my children."

He thinks back to the only time he had ever been unfaithful and says..."My God, are you the stripper from my bachelor party that I made out with on the pool table with all my buddies watching, while your partner whipped my butt with wet celery?"

Suddenly looking very uncomfortable, she answered "No, I'm your son's math teacher."