My stepsister Chiharu asked me to be her nude drawing model for an art school assignment. Knowing her brother has a gentle personality, she felt confident he would agree—and indeed he did. But under her intense gaze, his penis involuntarily stiffens. "I want to draw this part of you properly, big brother!" she says sweetly, staring intently. Though flustered by her eyes, he continues posing. Chiharu carefully sketches his body, and once the drawing is complete, she promises him a reward. That reward turns out to be a handjob and blowjob. As he receives these pleasures, his relationship with his stepsister begins to deepen. Captivated by her kindness, he eventually crosses the line. Responding to her passionate advances, his feelings grow in return, transforming their bond into something entirely new.