When someone gets so excited that they say "dude, this was so...!" and they proceed to descibe something in a way that only they, annoyingly enough, can understand. They get excited to the point where they jizz in their pants.
"Hey dude, did you hear about the new ride at Carowinds? dude, i heard it's so awesome dude, we gotta ride it, dude! dude,dude,dude!!!!! i just had a Dudegasm!!! Omg!!!