四畳半一間アパートで子持ちドスケベ隣人と汗だく濃厚なお付き合い

In the old apartment where protagonist Shuhei lives, single mother Kyoko and her son, Ohharu (a young boy), live next door. One day, when he helps Ohharu out in trouble, they become friends and she treats him to dinner. While Shuhei is enjoying a peaceful time next door, he accidentally learns about Kyoko's masturbation habits and accidentally gets an erection. Shuhei panics, but for some reason, Kyoko reaches down to his crotch and begins rubbing his erect penis. The two try to caress each other without Ohharu noticing, who is engrossed in anime, but things finally get out of hand... They end up fucking until they're drenched in sweat, day after day, in the 4.5 tatami apartment! (Source: Dlsite translated)