Aneki... My Sweet Elder Sister 1

The film is based on the manga series by Yoshu Ohepe. Takumi can't seem to get enough of Saki's luscious senpai's form, which makes her stand out from the crowd everywhere she goes. He and the woman strike up a conversation one day on the train, and the two become friends. Takumi looks at her shape whenever he has the opportunity, always getting a hard-on. When he returns the following day, he discovers that they share a fetish... and thus the narrative starts.