My Paranoid Next Door Neighbor(2004)

Tonari no Heya no Paranoia

Childhood friends and now high school seniors, Hokuto and Yukito will both be living in Yukito's family's house. Hokuto is actually Yukito's first love, and because of that, Yukito's been avoiding him since middle school... Upon meeting again after such a long time, Yukito's heart throbs at Hokuto's now very handsome appearance. However, without knowing those feelings, Hokuto seduces him! This piece of work is full of fun and even has new, never-before-seen parts!!

(Source: 801 Media)