Ore No Ie No Koakuma Imouto

mao-chan is a cheeky high school girl who loves to tease her virgin big (step)brother in naughty ways. however, her true intention is actually…?(source: (https://booklive.jp/product/index/title_id/20063387/vol_no/001))—note: the original pixiv series has been collected and published into 2 volumes.volume 1 (上) “up” contains chapters 1-20. volume 2 (下) “down” contains chapters 21-42.