JUR-840 "Mom will teach you an adult's kiss..." The inexperienced husband's stepchild's lips and virginity are taken by the voluptuous stepmother Shiraishi Marina.

Marina married a man with a stepson and started a new life together. Her husband's stepson, Satoru, had never known his mother's love and built walls around himself, but gradually opened up to Marina's maternal affection. However, one day, Satoru, unaware of the proper distance between parent and child, asked Marina for a kiss. Clumsily, forcefully having her lips taken, Marina's maternal instincts are stimulated to the point of madness. Marina admonishes Satoru, who is desperately forcing a passionate kiss, saying, 'Mom will teach you how adults kiss,' and gently guides him...