one whose breath has a scent which would indicate their mouth and a penis have been spending a lot of time together. this need not be applied literally and be used simply to deride someone or make them feel bad about themselves.
1. person 1: i like chloe, shes nice.
person 2: no shes not, shes a dumb bitch.
person 1: nu-uh!
person 2: look penis breath, just because you were so busy giving your dog a rim job that you didnt notice that i'm smarter than you doesn't mean that im not smarter than you. she's a dumb bitch.
2. person 1: you have terrible taste in music.
person 2: no i dont, metallica fucking rocks.
person 1: exactly, penis breath.