Just like normal nostalgia, but when you remember a time when you were a dumbass instead.
Jake: "Dude I just remembered that time in 7th grade I dated Meghan."
Will: "Ew that ugly bitch?"
Will: "That's some serious dumbass nostalgia, Jake."
Coach dumbass is the coach that loves to do shit like bang his head in walls and forget to start the clock for practice. Often sets himself up to be the butt of the joke.
Man coach dumbass is really on one today:
a random kid you meet online in a video game, usually halo, call of duty, battlefield, or gears of war. they think they are the best players ever, but actually suck.
This kid just picked up the boomshot and killed himself, what a dumbass random.
A founding father of any given field who was terribly incorrect, but is worshipped nonetheless.
Freud is the Daddy Dumbass of psychology.
When someone is so dummy thicc, they enter a new realm of thicc.
Damn, dude, that chick is dumbass thicc!
The consummate dullard, surpassing Alexander and lesser Dumbasses.
Then the contestant, reacting to the audience's laughter after she identified the author of The Three Musketeers as "Alexander Dumbass", said, "No...wait... Henry Dumbass!" -- from the Pardon My Blooper album, 1957.