Lady Scarlet was pretty mad that her crops failed and she investigated it and found out that her farmhand had not done what he was supposed to do. In short, he did not take care of the crops as per her instructions. So she punished him by shitting on him and surcharging him for what she had spent on the crops. That way, he knew better than ignoring crop care instructions.
Mistress Lola wanted a loyal assistant as she knew the field she worked in had a lot of betrayal. She made that very clear and she had to make sure that that was the case. She was therefore pissed when she found out that her assistant was disloyal and she had to punish him and fire him. This she did by shitting on him and he regretted what had happened.
Mistress Bastienne was shocked when her dad's friend tried to hit on her. She could not tell him to her father but she made sure that he would never try such nonsense on her again. So she turned him into a human toilet and made him eat her poo after making him think that she had given into his advances. He was shocked and he never tried it again as he feared her.
Princess Nikki had hired a private instructor as she wanted to get certified quicker but he did not do what she expected him to do. He was focused on her beauty and trying to sleep with her. The mistress got pissed and she used her shit fetish to punish him and make him focus. He was scared and he apologized profusely before concentrating on his job as he knew she was capable of worse.