What is Guatemalan Water Pump?
A standing sexual position in which the man is behind the woman, who is bent over with her hands cuffed behind her back. As the man "pumps", he moves the woman's arms up & down, while putting his finger in her ass. At the moment of climax, the man pulls his finger out as the woman simultaneously ejaculates and shits.
While vacationing in Antigua, I hired a tuba player to come back to my hotel room and play while I gave my wife a Guatemalan Water Pump.