Shounen ga Otona ni Natta Natsu

The protagonist, Ryuki Kirishima, lost his parents in a car accident at a young age and lives with his older sister Reiko. He feels that Reiko is the best person in the world. Ryuki hangs out in a warehouse at a secret base and watches a video of the supernova “Kiril-sama,” who is the talk of adult video sites. She has large, soft breasts, a waist that can be described as perfect, and an overwhelmingly fleshy ass. Ryuki had never reacted to pornographic videos before, but Kiril was different. And when he runs into the forest overwhelmed with excitement, he can’t believe it, but Kiril is there.