refers to the action of pulling your penis downwards, whilst pushing your scrotum forwards with your legs, so your balls get pushed either side of your cock. A succesful procedure should resemble the most disgusting chicken on the shelves in the super-market.
Anand: "Wait, I know a shortcut...take this left here...quick turn right again! Oh you were too slow, now we have to wait"
Cab driver: "What? You wanted me to take a left to miss to miss that traffic light and go through another traffic light?? What a silly man, what a stupid Sainsbury's manoeuvre!"