Lady Dominika felt that this guy was ill behaved and she had to deal with him. She did not want to let others deal with him so she used her shit to punish him. He was scared shitless when he realized what she was willing to do to him. The mistress made him eat poo and he did as he cried but she did not care as she felt he had brought it all on himself.
Lady Dominika knew this guy had a thing for her and she took advantage of that to make him eat her shit for fun. The fun was majorly hers as the guy was humiliated and he could not enjoy eating poo and drinking fun. He was actually scared and he did what the mistress wanted out of fear. She, however, had a lot of fun as he ate her shit.