Uso ka Makoto ka
ウソかマコトか · うそ か まこと か
est. Rough estimate based on volume count, reprints and magazine — not an official figure
Overview
One day, Taiyou, a popular guy because of his good looks, was asked by a senior student at his part-time job to take care of his cousin, Tsukihiko, who is attending the same university as Taiyou. However, Tsukihiko is rude to him from the beginning to the end, Taiyou still tries to be lenient towards him, but on the inside, he's on the verge of exploding because of him! Suddenly, Tsukihiko confessed his feelings to Taiyou and took him to an empty classroom where he made his move…! (Source: Core Magazine, translated) Note: Includes an extra chapter.
Source: AniList
External databases: MADB · AniList
How to compare editions, collected volumes and ISBNs / Sources, updates and corrections