This mistress was gassy and she needed to relieve herself. She felt that the best way to do so was to use her farts. That's why she chose to fart on this guy and have fun humiliating him for her fun. He had never been made to lick and smell farts so he did it because he was scared of what she would do to him if he refused. He did not want trouble so he cooperated.
Mistress Mystique did not want to deal with this guy because she felt that he was unreasonable. She did not want to deal with such a person and that is why she went out of her way to humiliate him. He cried at what she did to him but she did not care. She had his face covered with her huge ass and she even farted on him and he nearly choked.
This mistress had a weapon at her disposal and that weapon was her farts. She did not want to use a lot energy to punish and cruelly torture this loser. That is why she decided to use farts to punish the guy and humiliate him like he had never been humiliated before in his life. The guy cried and begged her to stop as he thought she would shit on him.