It’s clear from the insistence in this chapter that Mel is “just a child,” as well as from the introduction of a new character to serve as an external conscience by explicitly raising the issue of pedophilia, that Itou Hachi enjoys constructing and then performing on a very idiosyncratic moral/ethical tightrope.
It would have been easy enough to construct the story so as to mute its (as random says) unfortunate implications—Mel could be a bit older, the beastkin could be established as maturing much earlier in life, or there could even just be a flat-out introductory statement, like in her other works, that “it’s a yuri world, one where age-gap is perfectly fine.”
But no, she insists on walking that tightrope, with some of us down here yelling up, “Go for it, Master! Yuri overdrive!” and some of us saying, “Get down from there before something awful happens!” and some of us silently thinking some of both.
At least there’s a giant mattress of some of the finest cuteness in the universe to soften the landing if she falls.
(PS: If I want more Master/Mel bath scenes, is that bad?)