Confused af by the final sequence. It was all a dream?
Kaoru fell asleep in the tub and dreamed all her flirt with Mayoi?
Kaoru fainted from Mask grabbing her booty, maybe jokingly. Then later on after their exchange, in the evening when Karou was home she was taking a bath, she looked at where Mask grabbed her booty, and from thinking about the exchange + the heat of the bath she passed out.