[Tayanumaya (Tanuma)] Kyo kara warui ko [Kirby]

A seemingly innocent younger sister with twin hair buns and wide, sparkling eyes shocks her onii-chan by announcing, "I'll be a bad kid from now on," as she initiates a deeply intimate encounter with him on the couch. Despite her blushing protests that she is "reacting to this pretty well" and asking him not to touch her so much, she quickly escalates from teasing him to instructing him to "continue after dinner" and leading him to her room. The tension reaches its peak when their father catches them, forcing the boy to question what his sister's strange behavior truly means as she walks away with a knowing smile.