Lady Scarlet did not like how slow her slave was and it made her feel like plucking her hair whenever she had to explain things to him. She had to make sure he stopped being slow and that he improved himself. That is why she chose to pee on him so that he associated being slow with being humiliated and that is how he slowly started taking steps to address areas of inadequacy.
Mistress Nica got pee on her boots and she had this loser lick her boots clean. She did it to humiliate and dominate him because she did not like the way he handled issues. In addition, the mistress used the same boots to trample him and to kick him in the nuts. He could do nothing about it and had to learn never to piss her off as he would lose out big time.
Mistress Gaia had low regard for this loser. She tried to stay out of his lane because she knew if he messed up with her, however slightly, she would not hesitate to beat the shit out of him. Unfortunately for him, their paths crossed and she did not even beat him. That would have been better. She did worse by making him drink her pee. She dipped her toe in the pee in a bowl and he had to lick it from her feet as well as from the floor.