When you say ass, are you judging the entirety or the anus? Maybe you could sub out their anus as a stand alone. Could separate out tits and nips also. Or just add in a comment on anus or nips if they catch your eye, good or bad.
_________________________
Thinking of cracked-out and/or tweaking whores getting their throats and asses brutalized for the next hit makes me hard. --Rear Admiral