完堕ちXギャル母娘〜マジ気持ちイイ！アタシたち、アンタの肉オナホにされちゃう〜

The protagonist, Kiritani Atsushi, due to his father's remarriage, ends up living with his new stepmother and her daughter. However, his stepmother and stepsister are outrageously vile women, and Atsushi's life is getting ruined. Unable to bear it anymore, Atsushi consults with an acquaintance he met through an online game.

"Hehe, then, I'll give you something good. So good that it'll change your life."

Thus, with the special hypnotic drugs he received from his acquaintance, Atsushi begins to take revenge on the gyaru mother and daughter.

[Translated and edited from DLsite]