these are all considerations for the 'damned' one; 'not having a shittin' damn thing'. this is real fun to accuse friends of, too: they go, huh? -you can even add that old college flair by changing it to: you aint'snt gotta shittin' damn thing! one MUST be able to 'speak to impress' when dealing with employers, 'officials', little lord fauntleroys, etc...
were a 'lingual translator' actually to 'pick the statement apart', it would probably loosely be translated thus; you are such a douche-bag you can't even produce a turd. -throwing in 'damn' sort of colors the statement, or perhaps curses or dooms the scenario.
the beauty of the statement is its' final verbal polish on the tongue! it just rolls off like a fine wine sauce, plus! you get to sound highly educated!! -so, how can you lose? such a win-win situation for all!... -the stuffed-shirts all go huh? and the 'hop-heads' all nod approvingly!! ('shittin' can be replaced with 'shitting' for graduate students!!)
get wise! you aint'snt gotta shittin' damn thing!
he accused his friend of not having a shitting damn thing!