charcoal puffer

A phrase arising from the medieval alchemists of old. It refers to someone who who puffs and blows on charcoal in order to get more heat from it, that is a person who is full of wind (shit). It is synonymous with the phrase "To blow smoke up someone's ass". It also refers to someone who expertly talks about a subject with no real knowledge of what they are actually talking about. See also: bellow blower.

Don't listen to that charcoal puffer, they don't know what they are talking about.