Konomi ja Nai kedo - Episode 1

Tired of his rebellious little brother, the Older Sister aggressively berates Ritsuki for being home, calling him an "uggo" and a "pervert." When Ritsuki returns dripping wet after a bath, she is disgusted by him. Her hostility turns sexual when she feigns a sprained ankle and forces him to massage her, immediately escalating the act by groping his buttocks and touching him in "weird" ways. Despite Ritsuki's pleas and protests that "we can't go any further," she continues the erotic massage on purpose, touching his breasts and "sweet spot" until he comes. The sister then masturbates Ritsuki, hitting his arousal, and she too is visibly aroused and coming. After their mutual sexual release, the sister reveals she's been using Ritsuki as a sexual outlet because she had recently broken up with her boyfriend and was "all sorts of pent up." Their relationship remains one of mutual hatred, despite her explicitly using him for sexual gratification. The episode ends with the sister leaving Ritsuki alone in their room again, despite them being in a sexually charged state.