Shit Cert
When someone's breath is so bad, that even after inserting a refreshing Certs Mint Candy, their breath still reeks like shit.
Kyle: Dude, your breath is rank ass nasty! You need a breath mint.
Dwayne: Braaaaa I just ate a couple of breath mints. It should smell minty fresh.
Kyle: It ain't working Braaaaaa! What kinda mint was it? A Shit Cert? Smells like someone shit in your mouth.