A fun sucker, downer, negitive nacy party pooper or a downright joy killington.
Person 1: Man, lets go on a killer adventure!
Person 2: (AKA Fun sponge) Naw, im kinda tired. Plus adventures are for losers.
A sponge that allows for fun.
Random man: I don't want to wear a rubber.
Paula Abdul: Don't worry, I'm using a fun sponge.
Somebody who soaks the fun out of everything.
Damn, Jeff is such a fun sponge. Hw won't even let me fuck his sister.
At first I thought you were cool but you ended up being a fun sponge.
a person who is not cool and does not like to have fun
Nick is not a fun sponge even tho people think he is a duche, he is the coolest person around.