Having unexpectedly acquired an aphrodisiac, I decided to test its effects on my sister-in-law, who lives with me. I secretly gave her a drop every day, and she gradually began to act strange. Her body was hot and sweaty, and she twisted her hips, and even the slightest touch of my hand made her let out a sweet sigh. Then, after a week had passed, my sister-in-law, who had become a complete slut, could no longer resist and began masturbating, so I barged in and, when I showed her my erect cock, she lost all sense of reason and started sucking it. I squeezed her big tits and thrust it into her dripping wet pussy, and she showed me her ahegao face as she climaxed repeatedly. But it wasn't over yet, until I had turned my nagging sister-in-law into a human urinal...