Tapping :  (noun)

1: the sound of light blow or knock; "he heard the tapping of the man's cane"

aspiration, banging, blasting, bleeding, bloodletting, broaching, bursting, cracking, crashing, cupping, drafting, drainage, draining, drawing, emptying, exploding, explosive, flapping, knocking, milking, phlebotomy, pipetting, popping, pumping, rapping, siphoning, slapping, slatting, sucking, suction, venesection,