Color of Sky, Color of Water (2006) +18

Original title: そらのいろ、みずのいろ

The story revolves around two high school girls. Asa Mizushima (水島朝 Mizushima Asa) is a transfer student who soon joins the swim club to get her mind off her parents' divorce. She is confronted by Hajime Saisho (最所弌 Saisho Hajime), a cocky high school student. He persuades Asa through photography to capture her beauty, which she takes a liking to, but not at first. Asa is soon taken in by Hajime and intercourse ensues. Natsume Sorayama (空山菜摘芽 Sorayama Natsume), the second girl, who appears younger than the other two characters, takes interest in gardening. She overhears Asa and the teasing Hajime in conversation while she is hidden in a sunflower garden (conveniently located beside the club pool). While they engage in sexual activity once again, Natsume takes part by her own free will.