2-SAI SA NO OSANANAJIMI

He was just a childhood friend, like a cute little brother. But now, six years later, he is…… Even before we started dating, and now that we are going out, I can still feel my heart getting all flustered. (Source: Kadokawa, translated) Note: Originally self-published, was then licensed by Kadokawa for commercial release. — Description from AniList community (anilist.co).