https://www.dmm.co.jp/dc/doujin/-/detail/=/cid=d_575259

Prequel (Raw): https://e-hentai.org/g/3332687/33dda829d5/

[Synopsis]

In the previous story, Kurumi [the younger sister] and Shinji [the older brother] are step-siblings who developed a sexual relationship.
Since then, they have become obsessed with sex and each has become a sexual outlet for the other...
This time, their mother goes on a trip, leaving them alone...
Now alone, there's no one who can stop the siblings...
The brother and sister's sex life is free to do whatever they want!
What will the outcome be for the two?

[Character Introduction]

[Step-sister]

Kurumi Takasaka (♀) is a busty gal high school girl with a deep interest in anything erotic.
She has adored her older brother, Shinji, as a step-brother since she was a child and even after reuniting for the first time in ten years, she remains as attached to him as ever.
She is addicted to sex with her older brother, Shinji and creates all kinds of erotic events for him!

[Step-brother]

Shinji Takasaka (♂) is Kurumi's step-brother and a virgin... or so he thought.
In the previous story, his step-sister, the gal, Kurumi, took his virginity and he finally lost his virginity...
From then on, he indulges in sex with Kurumi...
His physical compatibility with Kurumi is outstanding and he has become his sister's favorite brother!
In this story, he continues to unleash his sexual desires on his sister...

Base +28, nuts987 +14