Part 1 (Raw) - https://e-hentai.org/g/3621742/5922c66f5b/

https://www.dmm.co.jp/dc/doujin/-/detail/=/cid=d_278946/

[Synopsis]

A few weeks after being raped by her stepbrother, Mai was forced to satisfy his sexual needs almost daily...
One day, Mai received a call from her stepbrother at school.
This was the first time the two had met at school and Mai, confused, headed to see him.
However, as expected, his purpose was sexual satisfaction and she was ordered to satisfy him at school...
After Mai had satisfied her brother's needs, something strange began to happen to her body...

Base +28, SokaiMaika +6, nuts987 +14

Yeah, Mai is falling apart, she is starting to like what Takuya is doing to her. I would assume a third part will wrap it up, Mai completely forgets her boyfriend and is forever Takuya's slave.

Unless this does very well somehow and Ushio steers Takuya towards his stepmom in more books?

Base +9, nuts987 +14, THeVaSHok1 +6