A guy in a supermarket.
A beautiful blonde waves at him and says 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 are the father of one of my kids."
Now he thinks back to the only time he has ever been
unfaithful to his wife and says, "My gawd, are you the stripper from my bachelor
party that I laid
on the pool table, with all of my buddies watching, while your partner whipped
my ass with wet celery and stuck a carrot up my butt?".
She said, "NO! I'm your son's Math Teacher!"