Minami is a female teacher who has always been self-conscious about her big ass. Troubled by the feeling of students' eyes on her backside, she struggles to live confidently. One day, she discovers a strange method to relieve her stress—rubbing her body against a student's erect penis. When a colleague accuses her of sexual harassment for violating school discipline, she's subjected to small-butt exercises and teased by her trainer, awakening new sensations within her. Realizing that men are actually attracted to her big ass, Minami begins to embrace her body and gain self-confidence.