this may just be a philadelphia term. so dont thumbs down unless you know for sure.nigger babies are what my mother and family and friends sometimes referred to as when you rub your hands together and they are dirty. little strings/balls of dirt roll up. nigger babies.
mom:go wash your hands before dinner
kid:their not dirty!
mom:like hell! go wash up now!
kid: i just checked for nigger babies tho!
mom:nigger babies or not you aint getting any food till you do!