On the seventh day of continuously administering aphrodisiacs to her large-breasted stepmother, who is four years her senior, she degenerates into a woman in heat due to persistent and intense incestuous sexual activity. Okuda Saki SSIS-699

After his father remarried, his new stepmother, Saki, was only four years older than Hajime. Hajime had always harbored desires for this young, beautiful, voluptuous, and still youthful-looking stepmother. Hajime, a pharmacy student at university, concocted a drug and secretly gave it to Saki. A few days later, Saki's body began to change... Every day, she indulged in the pleasure brought by her young stepmother's body, which had been seduced into a promiscuous woman.