No matter what this Jewish husband did in bed, his wife never achieved an orgasm.
Since a Jewish wife is entitled to sexual pleasure, they decide to consult their 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 your 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. It does not help and the wife is still unsatisfied. Perplexed, they go back to the Rabbi.

"Okay," he says to the husband,  "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.  They go home and hire, the same strapping young man. 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 soon she has an enormous, room-shaking, ear-splitting screaming orgasm.

The husband smiles, looks at the young man and says to him triumphantly,
"See that, you schmuck? THAT'S how you wave a towel!"