That JAV

My younger sister ran away from home after a fight with my mother. The reason for the fight was about her new boyfriend... I stayed over for the night with mixed feelings. The two siblings sleep together on the same futon while my brother is at a loss for what to do with his sister's unguarded appearance as she changes clothes without a care in the world. The brother is in agony, and he can't help but be aware of his sister's body... He can't control his growing fantasy and jealousy towards his boyfriend, who is playing with his sister's body, which he thought was just a child until recently, and he fucks her, forgetting about himself.