https://www.dmm.co.jp/dc/doujin/-/detail/=/cid=d_364645/

So she becomes her boyfriends mistress? Did I read that right? And there's a part 2? This might be interesting.

Base +8, mikegood -7, Koaen -30

@vjbeal96
You read that completely wrong. That bald guy is not her boyfriend, he's boyfriend's father.

Base +7, Shiro_ Ecchi +11, mikegood +7, Koaen +39

>The last summer vacation of high school life.
>The heroine, Takamiya Satsuki, was heading to the local summer festival with her younger sister Sana and her boyfriend Hiroaki.
>Satsuki and Hiroaki are childhood friends and a couple of the same age. However, Satsuki had a secret that she was hiding from Hiroaki.
>Three years ago, on the day Satsuki and Hiroaki started dating , Satsuki was instructed by her mother to visit a room in a certain apartment.
>There, Hiroaki's father was there... Satsuki's mother was Hiroaki's father's former mistress. Satsuki was forced to become Hiroaki's father's mistress due to her biological mother's selfishness.
>Satsuki, who despises the two of them, kills her heart and tries to get through the situation, but she reaches a spectacular orgasm with the hands of a man who knows her mother's body well...

Base +20, Koaen +39

@zentiran
Ah so that's what it was. Thanks for the correction.

Base +8, Asarta +6

nice book thx

Base +7