The act of perusing through a club or a party in search of a female counterpart which one escorts to the bathroom. Then one to unzips their pants and dunks their genitalia in the mouth of the newly acquainted female for a brief moment. Instead of allowing her to perform oral pleasure resulting in climax, one swiftly removes their genitalia from her mouth and returns to the pursuit of a new female counterpart. This is repeated as many times as possible in the course of an evening.
Oh man let me tell you about all the bids
last night, I was zip dunking so excessively hard that I sprained my wrist. Straight up Michael Jorin
Verb: The action of showing your junk. Also known as unzipping your pants and your large tool hitting the ground making the ZIPPP DUUNNKKK, sound!
Damn, Giac zip dunked that girl last night. All she could say was "DAMN!".