An older Jewish gentleman marries a younger lady and they are very much in love. However, no matter what the husband does sexually, the woman never achieves orgasm. Since a Jewish wife is entitled to sexual pleasure, they decide to ask the rabbi.
The rabbi listens to their story, strokes his beard, and makes the following suggestion. "Hire a strapping young man. While the two of you are making love, have the young man wave a towel over you. That will help the wife fantasize and should bring on an orgasm."
They go home and follow the rabbi's advice. They hire a handsome young man and he waves a towel over them as they make love. But it doesn't help and she is still unsatisfied. Perplexed, they go back to the rabbi.
"Okay", says the rabbi, "let's try it reversed. Have the young man make love to your wife and you wave the towel over them."
Once again, they follow the rabbi's advice. The young man gets into bed with the wife and the husband waves the towel. The young man gets to work with great enthusiasm and the wife soon has an enormous, room-shaking screaming orgasm.
The husband smiles, looks at the young man and says to him triumphantly, "You see, THAT'S the way to wave a towel!