If you've done any reading or watching, I'm sure there's something you really wish there was something else existing. Maybe it's rare and hard to find, or perhaps is hasn't been done yet (to your knowledge). I'm curious to the secret desires of other people around here.
For me, there needs more Sanae and Shinka, Chitose and Chizuru, Ayano and Kyouko, Yuri Incest, as well as more Threesome Honoka x Kotori x Umi and Rinne no Lagrange as well. I also wouldn't mind some Prunus Girl nsfw to round out the story.
