At a slumber party where everyone was supposed to be doing their homework, the naive girls happened to find a shocking lewd photo of their older brother's erotic book, and they couldn't control the urge in their lower bodies!

My sister and her friends have a sleepover to do their homework. The sisters ignore their homework and get excited about the erotic books their older brother has hidden away, but their heads are actually full of hate! ? Curious about the difference between the older sister in the photo and her undeveloped self, these naive girls are naughty and eager to learn while asking questions directly to their older brothers who are men, making their crotches flutter! ?