Miyuki is jokingly teasing her unpopular younger brother. Thinking that she is really inviting him, the virgin brother inserts his penis into his sister right after their parents leave. Miyuki climaxes from the force of it all, but her brother, who is not used to women, doesn't notice and continues to thrust his hips frantically. Even after climaxing, the pleasure continues, and he climaxes again and again, until their parents get home. He completely ignores his sister who screams, "I'm already cumming!!" and makes her climax over and over again with his wild thrusts!