"bad breath balls" refers to the smelly, yellowish-white balls that form in the back of the mouth. they are typically smaller than a pea and have a color similar to that of sesame seeds. they are also extremely pungent and likely contribute to halitosis though they are generally harmless and create only a minor nuisance. bad breath balls are also coughed up from time to time--often to the surprise of those who are willing to give them a whiff. bad breath balls are more formally referred to as tonsilloliths or tonsil stones.
i coughed up a bad breath ball that was like the odorous equivalent of a black hole--it was pure, concentrated stink.