Lady Fenja was in a fix and she needed help. She went to this guy who had her money and had in fact overstayed with the money and she asked him to give it to her as she was in a fix. He did not give it to her and she got pissed. So she used her sneakers to ballbust the guy until he gave her the money he owed her.
Lady Fenja used sneakers femdom to test whether this slave was suitable to work for her. She wanted to test his patience, endurance as well as his obedience before she hired him. The mistress used sneakers to dominate as well as to humiliate the guy. And she loved what she saw as he licked everything she told him to and he was obedient to the point that she stopped the punishment and hired him.
Lady Fenja wanted to make her slave more productive as she felt he was not on account of how unfit he was. So he could not finish simple tasks without being tired. And he was also unhealthy. So she kicked him with her sneakers and she humiliated him so that he learned to work out both for his and her benefit. His benefit by being healthier and her benefit by working harder.