pfffft!

A German guy approaches a lady of the night.

‘I vish to buy sex viz you.’

‘OK,’ says the girl, ‘I’ll charge  £20 an hour.’

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

‘No problem,’ she replies cautiously, ‘I can do 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…. Four-sprung  Duck technique’.