1. An internet meme and name for the sounds that a girl gamer (usually with big boobs) makes when she is really excited.
2. The act of splooging one's self when getting all hot and bothered by a girl gamer.
She's making memegasms because she just scored a pentakill!
Dude! You just memegasm'ed all over my keyboard! Get a hold of yourself man! She's not even that cute!