Mistress Nica did not like how inconsistent her slave was and she had to put a stop to that nonsense. She went to the horses' stable and she stepped on a lot of things some of which were dirty and then she summoned him and made him lick her boots until they were as clean as she had left in the house. And that is how he changed as he knew he had nowhere to hide.
Mistress Nica wanted to make sure this loser was not going to do the sort of things she knew he was used to doing. So the mistress cruelly trampled him after she had baited him with her ass and a little teasing. He had to endure the pain inflicted on him by her boots and he cried. He promised not to anger her again and begged the mistress for mercy.
Mistress Nica wanted to have a household that was disciplined. She loves order and she had to enforce it when she noticed that her slave was not doing what she paid him to do. She chose to use her boots to remind him that she was capable of making his life a living hell. So she brutally trampled him and she also had him lick her boots until she was satisfied.
Mistress Nica likes to have her way all the time and when she did not do so today, she was pissed and she punished the guy involved cruelly. The mistress did so using her boots. He had to lick her boots and she threatened to have her horse trample him if he did not do as she had ordered him to do. He had no choice but to comply with her orders.