Due to rapid weight gain, Kokoro decided to hire a yoga trainer to practice with the hope of losing weight and having a slimmer waist. However, gaining one thing meant losing another; in exchange for getting rid of the excess fat, she had to use her untouched body as a trade-off. The reason is that the yoga trainer was extremely handsome and lewd. He always knew how to please women, performing suggestive movements that stimulated the arousal of young girls, making it very easy for him to touch them or even engage in sexual relations.