Madame Marissa has a gorgeous ass and she knows it. This guy tried to spank her thinking that she would be flattered and would take it as a flirting gesture. But she did not and she was offended by what he did. She was so pissed at him that she had to degrade him and she did this with her hiking boots. He was shocked and humiliated by it and he regretted what happened.
Madame Marissa was out to boot torture this guy and she knew that she had to do it like a pro because she had to make sure that he learned his lesson from that one lesson. There was no going back and he had to do all that she said from then on. That is why she brought out her big guns and used the hiking boots to do it.
Madame Marissa felt that her slave did not do things the right way on purpose and she did not like it. She had to punish the guy and she chose to do it in a way that he would never forget. That is why she cruelly punished him with her hiking boots as she trampled his chest. He was in a lot of pain and he regretted what he had done.