Ai Shimai Tsubomi... Kegashite Kudasai
English title: Immoral Sisters: Blossoming
Japanese title: 愛姉妹 蕾…汚してください
Type: OVA
Episodes: 2
Source: Visual novel
Genres: Hentai
Studios: Arms
Producers: Pink Pineapple
Duration: 28 min per ep
Rating: Rx - Hentai

Katori is attracted to an enigmatic new student at her University named Koshiro. She remembers his face from when he saved her younger sister from a band of rapists in the past. However, rumours abound that Koshiro is sleeping with his teachers, and has some kind of hidden agenda against the school and her mother. When Koshiro's plan goes into motion, Katori, her sister, and her mother will all be in on the action.

(Source: ANN)