Mother, father and young son are visiting the circus. The elephants walk out into the circus ring and the little boy says to his mother, "What's that?"

"That's the elephant's tail," she replies.

"No, under the tail," says the youngster.

The mother is clearly embarrassed and says, "Oh, nothing."

The boy turns to his father and repeats the same question.

His father looks and says, "That's the elephant's penis, son."

"So, why did mum say it was nothing?" asks the boy.

The father draws himself up to his full height and says, "Son, I've spoiled that woman."