A gesture made with the hand by placing the tips of the thumb and index finger together. Like forming the "okay" sign but shown from the backside and below the shoulder. The idea is to get another person to glance at it, earning the right to punch them in the arm. The poonstance can be negated however by the viewer putting his finger through the ring that is made by the thumb and index finger. From a game often played by young adult males.
That guy just flashed me the poonstance and I looked right at it.
by Robble February 11, 2009