Mistress Mystique needed to scare this neighbor and she did it with her shit. That was the only thing she was sure would rattle the guy. So she did not hesitate to use her shit to do it as she felt that she did not have anything to lose by doing so. The mistress turned the guy into her human toilet and he had no choice but to eat her poo. He changed.
When mistress Mystique asked this guy to lick her ass, she knew that he would do it as well as she wanted it to be done. But he did not do it the way she expected and she was pissed at him. She had to punish and humiliate him for him to do it her way. So she cruelly made him eat her shit for him to know how to satisfy her next time.
Mistress Mystique felt that she had to dominate this guy in a unique way. In a way she had never done before. And so she went ahead to shit on him and to weaponize her ass. She choked him with the same ass before she pooped on him. And she also made him drink a mixture of her pee and her spit. She stopped as she felt she had humiliated him enough.