Kotaro struggles with overly sensitive nipples, yet he diligently trains every day solely to overcome this issue. While his body grows stronger day by day, his nipple sensitivity shows no sign of improving. One day, his mother's friend, Nozomi, suddenly visits his home. Suffering from a sexless marriage and deeply frustrated, Nozomi becomes intrigued by the sensitivity of Kotaro's body. Seizing a private moment, she reaches for his nipples. As she repeatedly sucks and licks them, Kotaro is overwhelmed by intense pleasure. Confused at first by this new experience, he gradually becomes addicted to Nozomi's relentless nipple torment.