Training Method of an Alpha: Totally Obsessed

Asahi and Kei are next-door neighbors who grew up together. Kei was always at his side, which Asahi believed would never change. One day, Asahi gets himself tested and is diagnosed as "a particular omega" and mentions it to his trusted best friend. Though he's an heir to a big toymaker, Kei's usually frank, down-to-earth, and a true alpha, but for...