This is a tsukkikage Au where kageyama is an age regressor and tsukishima is a care giver. It will start at the confession (3 months after school started) and not at the first day of school. This is not an Au where everyone is either a little or caregiver, just a select few who chose to be those.
This might include some angst and it will have some fluff. It may be a short book because I am not too verse on writing about littlespace and it was originally an idea I was going to put in a one shot book of Kiribaku but I noticed it was too long and it was too hard to find a story on little kageyama and caregiver tsukishima. The story will more focus on volleyball practice and their lives than actual matches against other teams.
I accept requests for things to be in the next chapters and I don't mind if you point out my mistakes so don't be afraid to comment.