The slave acted like an annoying idiot, which isn't really surprising. Mistress Naomi had enough of his stupidity and decides to punish him hard enough that he well act as a decent slave at least for a while. She kicks the naked slave in the balls more times than he could count, going harder and harder each time. The slave can barely stay on his feet and he also has to listen to Mistress Naomi yelling at him the whole time.