Please Miss Daisy Part 2.
Suffering enough pain for Miss Daisy eventually does earn this slave a reward, that of licking her bare feet. She knows that her feet make him weak so they are the perfect tool to completely break him and make him susceptible to having his cock tortured repeatedly with electricity.
She loves this as the grin on her face shows. In fact she could do this all day, watching him suffer intense pain to his cock over and over again as he grovels at her feet.