Grammatical rules are generally very relaxed with this word, as it can be used to describe a restraunt/eatery that serves food that one believes to be unsatisfactory.
Also, on occaision, this word can be used to describe people (most often females) whom one may deem fugly or aesthetically deficient. This useage of the word is debateable, as it would imply this person tastes bad, which may or may not be true.
Example 2 (restraunt): I aint never goin back to that chinese place down on East Main, that place is nappy meal.
Example 3 (person): Ugh dude, did you just say you thought Paris Hilton was hot? That bitch is nappy meal.