Well it's gotten weird but not dark at least imo that senpai girl surely took advantage of pure honest Asuka and we'll yeah she's an asshole but also Asukas honesty and trust is a little too overbearing, guess she learned somewhat of a lesson from the experience we'll see with the senpai girl.
But then again she straight up told a guy that had a crush on her and that she just rejected that she loved her mom romantically but hey who are we to judge her intelligence ? she trusted him lol.
Anyway I'm still rooting for her it's weird but hey that's what I'm here for this mother x daughter thing has been unexpectedly enjoyable and treated at least kind of realistically.
Masturbating on her mother's room ? Well it's clear she loves her and the room is full of her scent don't see what's weird about that, and she's just hitting puberty and developing her sexual appetite I think it's pretty normal you know aside from the room being her mom's.