Receiving an invitation to meet the long-time girlfriend from my close friend, I quickly went to his house to congratulate him. His girlfriend is a beautiful, fair-skinned girl with slender legs. That evening, I stayed over at his house, and while sleeping, I woke up feeling the need to use the restroom. As I opened the bathroom door, I was shocked to see his girlfriend masturbating vigorously. It turned out she had demanded sexual intercourse from him but was rejected, so she had to come here to satisfy her needs. When she realized I had caught her, she was very embarrassed, but her attitude changed completely when we went outside. Her eyes seemed to express a strong desire for me to help her relieve the intense craving in her body. That night, we committed a wrongdoing against my close friend.