Lady Phoenix noticed that this guy had tendencies of being an imbecile and she had to punish him for it. He was peed on and made to drink the pee. It was something he could not refuse and he had no choice but to do as the mistress wanted him to do. That is how the guy found himself crying and begging for mercy, both of which were ignored by the mistress.
Lady Phoenix and her friend had to find a way to tame this guy because he was unruly. They did not want to let him get away with his unruliness. That is why they went out of their way to pee on him. And he had to drink it all through a funnel. It was brutal and that is what ultimately made him learn his lesson and change as was required of him.