Lady Maria had a self indulgent slave and she had a great time dominating and humiliating him. That is why she chose to use her kinky foot fetish to dominate him. The mistress had to teach him a lesson that she had never done to anyone else. That is why she trampled him and she had him lick and smother her feet. He did it all as she wanted him to.
Lady Maria knows how to get her way whenever she is in a bind. She was in one today and she used her sandals to try kinky foot fetish. What she did threw this guy off balance as she was acting crazy and she managed to use that doubt and the resultant confusion to her advantage and she was able to get herself out of the mess she was in.