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