CRNX-017 The first time is with my little sister! My little sister, who is like an angel and becomes the practice partner for sex for her brother (a virgin) who just got his first girlfriend. Asuka Morise

Bright and energetic Asuka and I are siblings who tease each other. Lately, every time she finds out I'm a virgin, it becomes a joke. One day, I finally got a girlfriend! Asuka was happy for me at first, but then she started worrying, 'Brother, you don't have any sexual experience, right? If you're bad at it, you might get disliked.' Then she proposed, 'How about I teach you sex?' Though I thought that was wrong, I didn't want to be disliked by my girlfriend, so I decided to leave my body to Asuka...