A blauner is simply, a "fat" anything. A fat joint, or blunt is a blauner. Same goes for a fat individual, or human being.
Jason: Hey, lets smoke a blauner.
When referring to an individual:
Sam: Check out that blauner coming towards us.
**It is incorrect to refer to something as "a fat blauner." The word blauner implies that the subject in question is already fat, and needs no further adjectives to describe its "fatness."