My innocent and extremely introverted stepsister, after being harassed on the nipples for days, suddenly became hypersensitive and prone to premature ejaculation, experiencing frenzied orgasms! In the end, she transformed into a lewd woman with continuously orgasmic expressions. (Ayatsuki Nanao ROYD-318)

Because of my parents' remarriage, I suddenly gained a stepsister. She has an incredibly transparent and adorable personality, and honestly, I've always wanted to do something to her. My stepsister was originally very introverted, passive around assertive people, unable to express her opinions, timid, and cowardly. Therefore, even though I touched her nipples constantly from morning till night, she didn't complain; instead, she gradually began to experience pleasure, even to the point of drooling and her body twitching... The sensitivity of her nipples kept increasing, until finally she even came to me, begging me to touch her nipples. She already has a boyfriend, yet she's like this? It's simply an unbelievable pervert.