Sara-chan, a small and underdeveloped girl, trains with her older brother every day to become an adult. She stretches on her tiptoes to practice kissing him, and asks him to gently caress her flat chest to make it bigger. Furthermore, she begs her brother to inject his sperm into her hairless vagina so that she can become an adult woman sooner. Pure-hearted little sister Sara-chan continues her secret training with her brother until her small wish comes true!
