Placed in such a compliant environment as an inn with a mixed bath, Kouta can’t help but revert to his unrepentant, er, horndogging around. Smartly, the ladies prepared by having towels on under their towels, should he rip them off (which he does). Thus Kouta doesn’t accomplish everything he had hoped to, but just sharing a bath with the ladies is heaven enough for him.
The second half of the episode puts him through hell, as Senpai makes him drink an innocuous-looking bottle of water as payment for letting him goof off instead of accompanying the Occult Club on their trip to the Ookami shrine. That water turns out to be “oomizu”, or water that transforms the drinker into a wolf. Thus Kouta becomes the exactly what he can sometimes be described: a dog. A real one.
Moreover, he believes it’s divine punishment for his perverted transgressions. Unable to talk, only growl and howl, getting through to anyone is impossible; putting him in one of his biggest predicaments yet. But he learns he has nothing to fear, because whether he’s in wolf or human form, he’s Rurumo’s contractor, and she’ll always be able to recognize him and be there for him.
Rurumo’s rescue literally saves his life, which is a nice reciprocation of all of the ways Kouta has helped her. But this more than just a transactional give-and-take in which the two keep score of who’s saved whom how many times. Rurumo and Kouta just intrinsically want to help and protect each other. I’ve long given up on declarative statements of romantic affection, but their actions have spoken louder than words.