Father of my kid

A guy goes to the supermarket and notices an attractive woman waving at him. He's rather taken aback because he can't place how he knows her. 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 made love to on the stage while people showered us with whip cream?'

"No," says the woman, "I'm your son's teacher."