When the older sister comes to visit her hospitalized younger brother, she happens to see his erection. Since the younger brother is still a virgin, she asks the older sister to teach her how to treat a woman. Although she is hesitant, she feels sorry for her younger brother and cooperates, but the younger brother's dick gets harder and harder as she practices touching breasts, kissing, and even touching his crotch. The older sister is excited by this and finally gives in...