Hinako is a very innocent and inexperienced first year student at an all girls' high school. The night after Hinako meets her new roommate in the dorm, Seira, the other girl attempts to bring her to orgasm. However, Hinako finds herself unable to come. At her roommate's suggestion, she decides to study up on masturbation. Hinako's other friends--Karin, Nodoka and Ruri--are shocked when Hinako innocently brings up her masturbation problems in casual conversation. However, they're soon willing to take a practical approach to helping Hinako learn how to reach her own orgasm.

(Source: MangaHelpers)