OBA-287 From an accidental kiss to incestuous sex with a nephew

My sister's son, Masato-kun, has decided to stay at my house for about two weeks to take a summer course at a major preparatory school in Tokyo. Seeing Masato-kun, who was a spoiled child when he was young, has grown into a splendid man, I felt his charm not as his nephew but as a man. One day, Masato-kun's lips and mine touch each other due to an unexpected event. "This is an accident, it's not a kiss..." I tell myself, but I can't forget the feeling of my lips after a long time...