I'm confused. The previous omake chapters had me convinced they were already doing it, but they're embarrassed about showing underwear?
Yeah... the previous omakes I guess weren't meant to imply they actually went much further than was actually shown, I guess.
To be honest, the more I think about Tsukasa's situation, the more I realize she really
shouldn't have sex before getting her little 'immortality' situation handled. I feel like it would be unpleasant, if not outright excruciating, to do it if her hymen is going to virtually instantly heal the whole time. And let's not get into childbirth itself. People shouldn't be encouraging them to do the deed until this very big issue is resolved. And Nasa is certainly brilliant enough to find a solution, I figure.
To clarify, far as I've been able to piece together with the evidence presented in these first seven volumes, contrary to theories posited up until this point in the manga by other commenters, I'm convinced she is
not Kaguya-hime, but the moon-princess's tale (the Tale of the Bamboo Cutter) is most definitely connected. What I really think is going on is connected to the immortality elixir from that story.
So, the immortality elixir that was gifted to the Emperor by Kaguya-hime as she departed was supposed to be burned atop Mt. Fuji, right? What if it never got there? What if one of the people tasked with its destruction had a daughter that he wanted to protect more than his loyalty to the Emperor? What if Tsukasa was that daughter, and her father basically gave his life so his little girl could live on? This seems far more plausible than Kaguya-hime not actually returning to the moon and wandering the Earth for the hell of it.
It would certainly explain why she seems to be frozen at 16 years of physical age: that's how old she was when she took the elixir.
It also reinforces why Tsukasa has generally been presented as cold and distant at the start- she has gone through such traumatic loss during her thousand-plus years of life that she struggles to connect with others. Clearly, though, evidence suggests individuals in recent times have started to change that for her, including Nasa, obviously. Somehow he's broken through her shell and made her desire companionship in a way she hasn't dared to in all her time alive before.