I really liked this story. I was surprised at how well the author pulled off the feelings between the two, as well as the good and bad parts of each others' personalities. It may not seem psychological, only twisted, but there are little hints that show just how much their minds, not their bodies, led them to where they ended.
One who never wanted anything before, wanted something.
One who was never wanted before, wanted nothing.
Kawaii Senpai no Kaigoroshikata