Lady Mercedes expected total attention from her slave. But the mistress noticed that he was inattentive and she was not going to allow it to continue. That is why she opted to trample him. The mistress used her socks to do it and then she complemented them with her leather boots. It was painful and it was humiliating but he had no choice other than to do as instructed by the mistress.
Mistress Shelly wanted this guy to eat her pussy but he did it so badly that she was pissed and she regretted why she had even met him. But it was too late and she resorted to teach him how to eat pussy. The mistress did this by making the guy lick her feet and follow her instructions. And that is how the guy became an expert at eating pussy.