KissXSis
The story begins with Keita Suminoe, a male third-year junior-high school student studying for his high school entrance exams. He is living in a home with his older twin stepsisters, Ako and Riko, who share no blood relation to him, and they help him prepare for his exams. Even though he initially dislikes himself for it, he begins to become attracted to his two step-sisters, and his two parents encourage him to eventually get married to one of them.
Episode Summary
One of Keita's friends coaxes him into going to the pool with him and Mikazuki and inviting Ako and Riko. Suspicious of what they might be up to, Yūzuki decides to tail them. Whilst trying to hide from them in the bathroom, she is found by Ako and Riko who, mistaking her for a peeping tom, splash her with water. With her clothes soaked, Yūzuki borrows Keita's gym outfit. Later that night, Yūzuki becomes entranced by the smell of Keita's outfit and masturbates whilst wearing it and having sexual fantasies about Keita. She wakes up the next day to find that she had soaked his pants in the process.