A gishgasm is an orgasm that is resultant from a "rascal-like" act. This is typically an orgasm of unrivaled quality. The term is used primarily at a few small private universities but it recently has been heard as far south as kentuckey according to sources.
Person 1: Hey you wanna break into that frat house and steal their roofies?
Person 2: Yes of course I do, that will ensure they never have sex until a new shipment comes in.
Person 1 and 2 proceed to steal roffies and escape.
Person 1: Ahhhhhh! Gishgasm! (Passes out)
Person 2: Your such a rascal