A German approaches a prostitute. "I vish to buy sex viz you."
"OK," says the girl, "I charge 20 an hour."
"..ist goot, but I must varn you, I am a little kinky."
"No problem," she replies, "I can do that." So they go to the girl's place, 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 odd, but complies, fastening the springs as he had said.
"Now you vill get on your hans und knees." She does this, balancing on the springs.
"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 speak. "What do you call that position?"
He says: "It's the four-sprung duck technique."

it's probably really old but something I saw in other threasd reminded me of it