When you get so excited after performing impressive maneuvers, while playing a particularly difficult section of a Shoot Em Up, that you need to pause the game to clean your underwear.
Have you played Gradius 3 on the SNES using the new rom hack? My sphincter made a duck face and I think I had a shmupgasm while dodging the Moai rings on Stage 4.
Originally coined by two teenagers after they decided they needed to make up a word that accurately described them, Shmopsie is the epitome of awesome. Shmospie represents everything that is awesome, stellar, outstanding, cool, and fantastic and surpasses all of those things in every way.