Madame Ellen wanted to motivate this slave before he licked her boots. She knew he had a thing for her ass and that is why she used it to tease him. As he saw her curvy ass, he did everything she asked for as it was so gorgeous that he had a boner and he did everything to please him in hopes that he would be also get a chance to smash.
Madame Ellen did not want a slave who did not listen. She had to make him learn to do it or fire her so she decided to give him one try. But it came with a punishment as she cruelly trampled him and also had him lick her boots. But the major punishment was that she ball crushed him to make sure he would not want that kind of pain again.