Gerry goes to see his doctor and tells him that he's unable to make his wife orgasm and it's become a problem in their marriage. The doctor gives him a quick physical and can't find anything wrong, so starts quizzing him about other possible causes.

"Is your bedroom too hot or too cold?" he asks. Gerry tells him it's actually stifling in there, so the doctor suggests he get an air conditioner. "There's no way I could afford that on my wages" he says.

The doctor asks if Gerry has a close, trusted friend who he could ask to stand at the end of the bed and wave a towel to keep them cool. "I could ask my mate Tommy, I suppose" says Gerry.

That night, Tommy comes over and proceeds to wave the towel while Gerry gets to work. After half an hour the earth still hasn't moved so Gerry calls a halt.

"This isn't working. Let's swap places for a bit" Gerry says.

Tommy strips down and mounts up and within five minutes Gerry's wife is screaming "Oh God! I'm coming!"

When things have calmed down and everyone has their breath back, Gerry turns to Tommy and says... "Now THAT’S how you wave a towel!"