Asking for a place to stay to take the exam, the male student immediately fucked his sworn brother's lover

Yuzuru has to go to Tokyo alone to take the upcoming mock exam. He was allowed to stay for a few days by his senior, Kazuya, who had graduated from school. Kazuya and Yuko are lovers and both are living together. Yuzuru has also been fascinated by Yuko's beautiful breasts since he was in middle school. This time living with her made him extremely confused and nervous. He couldn't help but "salute the flag". Yuko added fuel to the fire by constantly wearing revealing clothes that showed off her big breasts. She also wrapped herself in a towel and forced him to dry her underwear for her, even Yuzuru could. admiring the lovemaking scene between her and her lover that night... Even so, Yuzuru still tried to control herself, not allowing herself to make a mistake. But the next night, when Kazuya had to come home late to meet a client, Yuko got drunk because she went out drinking, and Yuzuru had to help her to bed. He was about to leave but Yuko called him back. “Do you want to see my breasts?”, “Can I see your breasts?”, “You keep staring at my breasts.” Being seduced by Yuko makes Yuzuru unable to bear it anymore. The two continuously make love to each other when Kazuya is not at home. Yuko gave Yuzuru three days of summer that he will never forget for the rest of his life...