As morning light streams in, there's Kanna, braless in a tank top, straddling me and pressing her breasts against me. Pale-skinned and slender, she's always been concerned about me, noticing how inexperienced I am, quietly intrigued. Day after day, she'd expose herself without hesitation, closely watching my reactions. Beginning with a morning titty fuck, it escalates to toy play with electric massagers and vibrators, aggressive cowgirl domination, and repeated creampie orgasms—seven climaxes in total. A taboo 150-minute encounter between brother and sister, as he helplessly stays erect, tormented by his overly developed little sister's breasts.