Goddess Amanda had a need to dominate and humiliate this guy, which is what she did. The mistress used her shit to do so. That is because she knew that it was going to be cruel as well as humiliating for him but she did not care. All that she wanted was for him to eat poo and he did it just the way that the mistress wanted it to be done.
Goddess Amanda felt that this guy had to lick her shit and eat it too so she made him do it. The mistress made him lie down and she took a shit on him. When she was done, she smeared the shit on him and on herself. He did not even have the time to get shocked at what she did to him as she forced him to lick her shit.