A friend of mine, Jim went to the supermarket and noticed an attractive woman waving at him. She said hello. He was rather taken aback because he could not place where he knew her from.
So Jim said, "Do you know me?"
To which she replied, "I think you're the father of one of my kids."
Now Jim's mind traveled back to the only time he had ever been unfaithful to his wife and said, "My God, are you the stripper from my bachelor party that I made love to on the pool table with all my friends watching while your partner whipped me with wet celery???"
She looked into his eyes and said calmly, "No, I'm your son's teacher."