Sinais found talk of her tail's usage odd. She might have assumed that anyone with a tail should have reasonable control over it, it was an extra prehensile limb after all. "Hm I didn't think about anything like that, though I don't have much to go on. Mi-tan, keep a look out for anything interesting with extra limbs, I know you still want a few~" she mused as she began properly battering away at the other girl. Of course she would say something like that, even the face of hers which was least likely to admit anything claimed to want extra hands. Still, it could be stated that Sinais knew she wasn't an ordinary creature, she was always confirming for the other lass that they were special, perhaps that one would finally understand the meaning of that eventually.
For now, there was movement though the infinite depths. With Seigen plunging into Riri and Sinais working her way into Miko, those two girls ended up pressed against each other their bodies giving them extra sensation as they sank into water. This water didn't require breathing or anything of the sort. The pair in the middle could easily molest and accost each other while their holes were being filled by others. At the same time... Seigen seemed to acknowledge a certain looming presence in the space, one outside of their quartet. A smirk crossed that woman's face as she was acknowledged so directly, 'I may never get used to the types who seem to see me watching them. Have your fun, and careful with reality, it's still not very stable,' she gave that little warning while taking in the sights. Her presence wouldn't disappear, but instead it'd simply blend in a bit, she wasn't trying to observe but she also wasn't trying not to see, casual voyuerism would lead them to the next space. At the same time, Miko and Riri seemed to be reeving up. How long would it take for the pair to find bliss? Not very long as they were rocked against each other with nothing to hold them back, both girls would be found clutching at the tools within them while expelling their own fluids and singing the song of their orgasm.