Waterboarding is a form of water torture in which water is poured over a cloth covering the face and breathing passages of an immobilized captive, causing the individual to experience the sensation of drowning.orturers pour water onto the face over the breathing passages, causing an almost immediate gag reflex and creating a drowning sensation for the captive. Vomitus travels up the esophagus, which may then be inhaled. Victims of waterboarding are at extreme risk of sudden death due to the aspiration of vomitus.