PPPD-807 _Can't concentrate on work because my sister keeps flirting with me

Having just finished writing part of her graduation thesis, Hatori and her boyfriend immediately invited each other to have sex as a reward for their many days of effort. Ironically, at the height of climax, Hatori had to go to the bathroom. As soon as she left the room, her older sister Eimi, who had a habit of being naked at home, walked in, making them both accidentally see each other's bodies. Especially, the boyfriend kept staring at her sister's breasts while she only paid attention to her big penis with a dark plot hatched in her mind. The next morning, after her younger sister had just gone to work, with no underwear on, she stood in front of him and repeatedly used obscene words, expressing her desire to solicit the young man. Attractive body, lewd personality, beautiful face... all of these things she was many levels above her sister, so it was understandable that the other guy easily fell for her. Their secret love affairs began to go smoothly from then on until one day the innocent younger sister Hatori discovered she was being cuckolded...