Let's see

It looks like it's your younger son who's lucky enough to see his mom get freaky in the morning. He looked at you and of course he instantly got hard. He stood there for a minute and decided to whip out his dick, just to bust a nut to his mom playing with her pussy.

You are close to cumming and so is he.

You lay down on the bed and he goes to your room, what a show you just gave to your son and you didn't even realise he saw everything!