As a boy,he was stuffed in a sack and nearly beaten to death by Khmer Rouge soldiers simply for letting air out of a car tire.
VOA: standard.2010.04.19
When the rubber sack makes contact with an object, whether a glass, a pen, or other hard item, a narrow inner tube sucks a small percentage of air out of the sack, making it contract and conform to the shape of the object it touches.