Mistress Dula needed to know that her slave took her instructions seriously. That is why she went out of her way to dominate him and to make him lick the soles oof her heels. She supervised him as she was sure that he would not do it as well as she wanted if she asked him to do it without personally supervising him. It also helped her know how to deal with him later on.
Mistress Dula could tell that her slave had a poor attitude and she did not want to be associated with someone like that. So she did what she does best and she used her boots to dominate him. He was cruelly trampled and even made to lick the soles of her boots before she was done with him. He cried but the mistress did not care about his cries. In fact, she invited her friend to help her dominate him.