Mistress Ann needed to make sure that this guy knew who he was dealing with. She felt that he did not and for that, he had to be punished. The mistress chose to make him eat her poo and also to lick her asshole until it was clean. That is how she used him as a human toilet paper. He never messed again as he knew what would happen to him.
Mistress Onyx wanted to show this guy that she was not one to mess with. She used her shit fetish to do it and he was shocked but he ended up doing what she wanted. He was able to understand that if he messed with her, she would not hesitate to do anything she could to remedy the situation and to teach him a cruel and extreme lesson like she did today.