This mistress knew she was not going to tolerate having a lazy slave. And that is why she chose to facesit on this one to make him learn that it would be costly for him to be lazy in her household. He peed his pants as she ass smothered him and he knew his days of laziness were over if the punishment he had received was anything to go by.
Princess Serena did not like how her slave was a know it all. She wanted him to learn to do things her way and when he did not do that, she had a duty to teach him how she wanted things done and also to force him to observe those regulations. The mistress used her denim to ass sit on him and by the time she was done with him, he stopped being a know it all.