A rubber that has been in your wallet for far too long and is starting to crumble.
"Hey , Bae you ready for some sugar?"
"Ya, hang on."
"Shit, all I have left is this crumb rubber."
"It's cool Bae, this won't be my first kid."
"What?!?"
Frat term for banging a Mormon chick
"brah... pulled a MormonBuster last night" -ak