to squeeze, tug, or otherwise stimulate the penis to a plump, but still flaccid state, generally for appearances.
I was about to climb in the shower when Todd's hot little sister busted in. I was standing there naked, and I didn't even have time to chump up! I don't know which of us was more embarassed.
by terriblefish May 25, 2006
self-infatuation mentally and/or physically
daves' a nice guy for a pumped up chump!
by michael foolsley November 19, 2009