FSDSS-192 — Failure In Upbringing, No, Success: My Overly Boyish Little Sister's Rebellious Sex Sora Shiina

Little sister. You're a man. A real man among men. This girl was raised too boyishly and has zero shame. She wanders around naked, doesn't flinch when she sees her brother's (your) dick, and even tries to use you as a sex practice dummy. Don't mess with me! A completely subjective battle where you deliver a wrathful sexual blow to this sister who looks down on you with complete contempt. Come on, sperm!