"Onii-chan, I love you the most in the world!" Kokoha-chan with a dazzling smile attacked onii-chan! "Today, I'm going to learn about health and physical education from my brother," he says, looking forward to inviting his brother into his room. The study that takes place in a closed room with just the two of us covers everything from how to kiss to how to insert a penis...! A Younger Sister Who Is Thoroughly Educated Is An Older Brother's All-you-can-eat! ?
