I started dating my super shy step-sister who clearly likes me and has a super cute smile... But we haven't had sex yet... It's the first time we've spent two days and one night without our parents... This chance has finally come... Anyway, we're going to have sex! Anyway, we're going to have sex! As we're having sex until my step-sister gets bored, she gradually becomes bolder and in the end she turns into a super slutty woman, saying, "Cum inside me, big brother!"