"My brother, I love you so much!" shouts my niece, a sweet, girlish girl. Taking advantage of her innocence and naivety about sex, I pretend to care for her while secretly initiating sexual mischief. The scene captures my hands tracing the swimwear tan lines on her pale, delicate skin—a young, pure beauty in a school swimsuit. "Nii-chan... it feels kind of weird," she murmurs, yet innocently adds, "Big brother's penis is so big." Her genuine, childlike reactions slowly erode my self-control, driving me closer to the edge.