While My Girlfriend Was Away, I Secretly Spent The Next 7 Days Fucking Her Prematurely Ejaculating Little Sister Nana Yagi

Exclusive 4th edition! First challenge to Nana Yagi drama! My house had no electricity or gas, so I decided to stay at her house for a while. She has a younger sister, and I'm meeting her for the first time, but... she seems to be wary of me, sticking...