A German guy approaches a prostitute.

"I vish to buy sex viz you."

"OK," says the girl, "I charge 200 an hour."

"..ist goot, but I must varn you, I am a little kinky."

"No problem," she replies cautiously, "I can do a little kinky."

So off they go to the girl's flat, where the German produces four large
bedsprings and a duck caller.

"I vant zat you tie ze springs to each of your hans und knees."

The girl finds this most odd, but complies, fastening the springs as he
had said, to her hands and knees.

"Now you vill get on your hans und knees."

She duly does this, balancing precariously on the springs.

"You vill please to blow zis kwacker as I make love to you."

She finds it odd, but figures it's harmless (and the guy is
paying.)

She finds the sex is fantastic, as she is bounced all over the room by
the energetic German, all the time honking on the duck caller.

The climax is the most sensational that she has ever experienced and it
is several minutes before she has enough breath to say, "That was
totally amazing! What do you call that position?"

"Ah," says the German . . ."zat is ze... Audi."

"Audi?" Asks the astonished sex worker.

"Audi," replies the customer. "Four-sprung Duck Technique."