Mistress Sofi was not going to let this guy continue to be inconsistent with her and she did what she does best which was to facesit him and to humiliate him like she felt he needed to be. She used her ass as well as her feet and by the time she was done with him, he had gotten the message and he had learned his lesson and promised never to repeat it.
Mistress Sofi did not like how quiet this slave was. She felt that she had to punish him for being quiet so as to make him learn to talk. The mistress did not want to be in the same house with someone who did not tell her anything and she felt that it stressed her out and put a lot of pressure on her. So she facesat on him to make him change.
When mistress Sofi found out that this slave was insubordinate, she had to do something about it since she did not want to have a slave who was going to cause more harm than good to her. She had to make sure the slave would never do what he had done again and that is why she chose to choke him by facesitting on him and also farting on him.