https://www.dlsite.com/books/work/=/product_id/BJ01077226.html
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When my mother remarried, my stepbrother was a super scumbag ex-boyfriend: "We're family, but let me fuck you!"

She doesn't want to feel this man's dick, but when he relentlessly pokes her with his bare pink prick... she can't take it!
--Shuri is a high school girl who is happy to have a kind boyfriend. One day, she is introduced to the stepchild of her mother's new marriage, but it turns out to be her ex-boyfriend, who is a scumbag. Shuri is upset, but decides to keep quiet for the sake of her mother's happiness...
However, when the ex-boyfriend learns that she has found a new man, he forcefully pushes her down, saying, "If you have a boyfriend...you are not a virgin anymore, right?"
Shuri's body involuntarily reacts to his skillful fingering.
He humiliatingly makes her squirt repeatedly... "If I don't do this, he'll take away my happiness...!"

Felt a bit bad for the boyfriend but damn...that ending just says it all =_='

Thanks for the synopsis and upload.

Base +19, Fofotron +7, Shintaro- +6, yupokamusi -8