https://www.dmm.co.jp/dc/doujin/-/detail/=/cid=d_422002/

>Due to her mother's selfishness, Satsuki was forced to become Hiroaki's father's mistress.
>Although Satsuki despises the two of them, she accepts the relationship with Hiroaki's father, knowing that it is for the sake of maintaining a peaceful life.
>During their previous secret rendezvous, Hiroaki's father, who was very familiar with his mother's body, led her to a spectacular climax.
>On the day of their second secret rendezvous, Satsuki tells herself that the body's reactions are separate from the mind, and heads to the designated room...

Base +20, my little donger +8, darkwing42 +53