Do I know you?

A guy was in the line at the supermarket, when he noticed a beautiful blond woman smiling and waving at him.

So he says, "Do I know you?"

She replies. "I may be mistaken, but I think you may be the father of one of my children."

Instantly his mind shoots back to the one and only time he had been unfaithful.

"Christ!" he says. "Are you the stripper from my bachelor party that I had sex with on Joe's pool table in front of all my buddies while your girl friend spanked me with wet celery and stuck a cucumber in my ass?"

"No" she replies. "I'm your daughter's second grade teacher."