The Valsalva maneuver is performed by moderately forceful attempted exhalation against a closed airway, usually done by closing one’s mouth and pinching one’s nose shut. Variations of the maneuver can be used either in medical examination as a test of cardiac function and autonomic nervous control of the heart, or to “clear” the ears and sinuses (that is, to equalize pressure between them) when ambient pressure changes, as in diving, hyperbaric oxygen therapy, or aviation. (via @cyberu)
Whoa. That thing where you pinch your nose and try to breath out to (un)pop your ears has a name.