Boyish Kanojo wa Toshishita S Kareshi no Dekiai Choukyou kara Nigerarenai.

Tomboy Yuzu is popular with all the students in her year, boys and girls alike. She helps a lot of the sports teams, though, she she hangs out around boys most of the time.
Then one day in the school infirmary, she met a younger boy named Yousuke. He was resting in one of the beds, and they got to talking. Apparently Yousuke had no friends...Yuzu couldn't bear to leave him alone, so she started to spend time with him. He was so kind and gentle. Being with him was always so nice. She thought they would last forever, those happy lunch breaks spent talking in the infirmary...
Eventually, when Yuzu was a bit worried about boyish she was, Yousuke confessed that he'd always thought she was cute. She didn't know what to do. Nobody had ever really treated talked about her like a member of the opposite sex. She started to shake. When he noticed, Yousuke pulled her down onto the infirmary bed.
Without even giving her a chance to resist, Yousuke then started feeling her up, and eventually stole her virginity.
After that, yuzu tried to distance herself from her former friend, but Yousuke wouldn't have it. She was going to be his again and again, whether she liked it or not.
Will Yuzu escape from his control? Or will she lose herself to the pleasure of his touch...?