Contrary to popular belief, a power dump is a term used when one is so busy that time cannot be wasted!
Commonly used whilst raiding in World of Warcraft, and you want to remain top of the damage meter.... I suppose it can also apply to work, watching sports... whatever.
To save valuable seconds, you go in, and instead of relaxing and letting nature do the work, you push til you're red in the face and force that shit out and 100mph!! Followed by a speed wipe, then back to doing whatever it was you're doing.
Krasek: Gotta take a dump!
Kuro: Hurry dude, we're about to start on the last boss!
(30 seconds later)
Kuro: That was fucking quick!!
Krasek: Yeah I know, power dump FTW!! May have given myself a hernia though.