A guy goes to the supermarket and notices an attractive woman
waving at him.
She 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'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,
'Are you the stripper from the bachelor party that I made love
to on the pool table with all my buddies watching while your partner
whipped my butt with wet celery?'
She looks into his eyes and says calmly, "No, I'm your son's
teacher."