nuclear bunker

a place where you are safe from nuclear bombs

we should head to the nuclear bunker before we die

nuclear bunker ass

Exaggerating the fact that a person is so fat that his/her ass can be used as a bunker during times of a nuclear apocalypse.

"Shit mate! I heard WWIII is gonna start soon!"
"Naah, we'll be just fine mate! No need to fear when Danny's nuclear bunker ass is here!"