Kiss Me Manga

情深一吻

Fujishima is living in a cheap apartment complex because he has a small budget. The walls of the apartment are very thin and he can hear everything that happens next door, even the calls of "Izumi" during his neighbor's sex. The overheard sex eventually turns into over heard fighting which gets so out of hand that Fujishima has to go next door and interfere. To his suprize, Izumi was not the female he suspected to live next door, but the unsociable male he saw from time to time. Helpfulness turns into a crush and problems arise... (From Nanala3)