The act of taking ones hands and pushing up their boobs in a moderately sexual way in which the goal is to excite a man or multiple men. The most commonly used technique is when the hands of the "shelfer" makes a straight line or a "shelf" and lifts the breasts up, and then back down. The word "shelving" most commonly refers to women, however men can shelf their man boobs or moobs
for comedic purposes.
To get the attention of some guys at the party, Julie she decided to shelf.