MIAA-259 The virgin younger brother, genuinely taking his sister's provocation, doesn't notice he's climaxing and continues with violent piston thrusts. Reika Kuruki

Rei teased her unpopular younger brother as a joke. Her virgin brother misunderstood and thought she was really inviting him, so he immediately inserted his penis right after their parents left. Rei climaxed from the intensity, but her brother, inexperienced with women, didn't notice she had orgasmed and continued to thrust wildly. Despite reaching orgasm, the continuous sensation of his pistoning made her climax repeatedly, unable to resist until her parents returned home.