Kururugi Mikan, known as a strapon genius, usually plays the role of a gentle, sexy M-masochist sister type. But when the two of you are alone in a locked room, she reveals a completely different side. She cheerfully and innocently plays with a man's anus, hiding deep expertise in anal training beneath her playful demeanor. Through careful, meticulous stimulation, she brings him pleasure he's never experienced before, making him surrender his body in both shyness and comfort. In the end, the shocking climax arrives—she presents a strapon larger than a real penis and dominates the helpless, exhausted man with anal penetration.