Mistress Ava Black was stressed. She had had a rough day and she did not want any more stress from anyone. So when her slave messed, she reacted badly. She used her smoke to humiliate him. She had been smoking to try and calm her nerves but she used the cigarette to humiliate her slave as she used him as her human ashtray. She wanted him to learn to leave her alone when she was pissed.