A little boy answered the door and the gentleman asked if his mother was home.
The little boy said "No, she is at the whore house."
The bright salesman asked if she was a prostitute, and the little boy replied,
"No, she is a substitute. She only works Wednesdays and Fridays during the rush."
The salesman said, "Well I'll be a son-of-a-bitch. "
The little boy said "Well, I'm one too, but I don't go around knocking on doors telling folks."