Osananajimi to Ishindenshin?!
オさナなじみと以心伝心!? · おさななじみ と いしん でんしん !?
est. Rough estimate based on volume count, reprints and magazine — not an official figure
Overview
Saku and Azusa have been together. They were even born the same minute. Now that they're off to college, it's finally time for them to separate, and the ever-anxious Saku is feeling lonely while the calm and cool Azusa is as aloof as ever. One day, Saku suddenly hears Azusa in his head! What's more it almost sounds like Azusa is in the middle of pleasuring himself while looking at Saku's photo! Will this newfound power bring the two closer or will it drive them apart? (Source: MangaPlaza) Note: Includes one extra chapter.
Source: AniList
External databases: AniList
How to compare editions, collected volumes and ISBNs / Sources, updates and corrections