Lady Victoria wanted to pass a message to this guy that she could control him and make him do whatever she wanted and she did it by making him jerk off to her instructions. He could not believe what he had been made to do even after he had told her that she would not succeed to try and control him. But he realized she could easily do it and he learned to fear and respect her.
Lady Victoria wanted this guy to jerk off and she ensured that he did by forcing him to do so. She was doing it because she felt that he needed to cum and to loosen up as he was too uptight. He deserved to relax a little and she felt that that would be a good place for him to start. He felt humiliated but when he was done doing it, he felt good and thanked her.