This story centers around the close relationship between a brother and sister, beginning with casual conversation as they wash each other's bodies. The sister is well-endowed while the brother is well-hung, creating a striking physical contrast that adds to the allure. As they bathe together, their innocent contact gradually becomes more intimate. Adding to the tension is the surprising fact that the brother is still a virgin, heightening the charged atmosphere between them. Eventually, the sister openly expresses her desire to be penetrated, and the brother, clearly understanding her intent, begins passionately stimulating her. The climax features the forbidden act of creampie, making this a highly intense and compelling experience. This work captures the gradual evolution of their bond—from simple bathing to deeply intimate contact.