I thought this was cute. It's a different perspective on Yuina.

I'd actually prefer to see the ideas expanded, as it was a bit too short for my tastes. Particularly the second-to-last section where they get "frisky," and not just because I want to read erotica (though there is that too, kinda ) ) but because it seems like that's where you can explore Satsuki as the elder, exploring the power-relation between the two, and such ... honestly in this brief format it almost seems too abrupt, that Yuina is too forward ... Having a power-exchange between the two isn't bad, but (to my mind) needs more development than it is given here.

So in short, (in my opinion) good ideas that really need a longer treatment.