Mother-in-law incest - new mother's indecent sex education

Ayumi remarried a man with two young sons. Whenever I was doing housework, my sons would come over to talk to me about something, but I was having trouble communicating with them. One day, my second son accidentally catches me masturbating. The second son, who was around the same age, could not suppress his desire, and when he devoured Ayumi's body, he even ejaculated inside her. Who was the eldest son who was spying on them? ?