A guy goes to the supermarket and notices a beautiful blond woman wave
at
him and say hello.

He's rather taken aback, because he can't place where he knows her from.

So he says, "Do you know me?"

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

Now his mind travels back to the only time he has ever been unfaithful
to
his wife and says, "My God, are you the stripper from my bachelor party
that
I laid on the pool table with all my buddies watching, while your
partner
whipped my butt with wet celery?"

She looks into his eyes and calmly says,

"No, I'm your son's maths teacher."