I'm guessing that the point is to distinguish between a sentence like "she used to have long, blonde, wavy hair" and one like "he used to have thick, dark chest hair." You wouldn't put a comma after "dark" in this sentence, because "chest hair" stands alone as a unit: the word "chest" defines what kind of hair we're talking about, as opposed to describing what it was like. So in this case, the adjectives do not all apply equally.
As I said, though, this is a guess. (Well, correct as far as the information goes, but a guess as to what entangledbank meant!)