Hitozuma o Ecchi de Kudoku Houhou

The protagonist of this story is in love with Kiyomi, the mother of one of his friends. In other words, he's in love with a woman who is married with children. His passion turns into a sexual drive, and he attacks her in a frenzy! What methods will he use to seduce and woo her!?

Miyo, the self-styled elder sister of the protagonist, appears on the scene to erotically harass him. Her plan is to take his virginity! She throws the relationship between the protagonist and Kiyomi into disorder, both as a supporter of their love and as an erotic assailant!

[From DLsite English]