"Gomu o Tsukete to Iimashita yo ne..." (translated as "I Told You to Wear a Condom...") is an adult-oriented series that delves into complex interpersonal relationships and intimate encounters. In Episode 1, the narrative introduces the protagonist, a young man who becomes romantically involved with his girlfriend, Mamori. Their relationship is characterized by affection and exploration, with Mamori initially displaying shyness that gradually gives way to curiosity. As their intimacy deepens, the unexpected arrival of Mamori's assertive sister, Nanami, adds a provocative twist to the storyline. Nanami, embodying a more dominant and self-assured demeanor, confronts the couple and expresses gratitude towards the protagonist for his relationship with her sister. However, she simultaneously introduces an element of seduction, suggesting a desire to engage in intimate activities with him. This proposition creates a tension-filled atmosphere, challenging the boundaries of the protagonist's relationship with Mamori. The episode delves into themes of temptation, fidelity, and the complexities of human desire. The animation vividly portrays the contrasting personalities of the sisters—Mamori's innocence and Nanami's boldness—thereby intensifying the protagonist's internal conflict. The episode's climax centers around the protagonist's decision-making process, as he navigates the moral and emotional implications of Nanami's advances. Overall, Episode 1 of "Gomu o Tsukete to Iimashita yo ne..." sets the stage for a provocative series, emphasizing character development and the intricate dynamics of forbidden attraction.