Becoming a Motherfucking Motherfucker (Mom/Son Incest)

I'm leaning towards playing the son here.  The idea is a son who could either be teenager or young adult and a mid-upper 30s single mother.  The two have lived on their own as long as he can remember.  He has no other family, his mom being emotionally distant from her own family.  She has always been reluctant to talk about his father.  They lived a simple yet reasonably happy life, neither imaging how much would change one random night.  It happened purely by impulse.

I have a few different ideas for how this happens (open to other ideas too):

He comes late from school/work/other activities.  Does not see his mom and walks upstairs to head to his room.  On the way he hears strange noises coming from the bathroom in her bedroom.  Thinking she might have been hurt, and the music coming her room muffling the noise, he walks inside.  The noises get stranger once he is in her room but he pushes on, the door to her bathroom cracked open.  He silently pushes it open to watch her going to work on a dildo pressed against the shower door, her body still soaking from a recent shower.  He could not help but watch.  After a few minutes, he could not stop himself, from unzipping his pants and jerking off to his mother masturbating of all things.  He had never seen her like this before, in any sort of sexual atmosphere.  But she was still a woman, with natural desires.  Maybe he could have snuck out and pretended nothing happened.  But then she tripped slightly, catching herself before falling, but the music stopped her from hearing the door slide and the dildo fall.  Panic and lust motivated the next step.  Before she realized what happened he stepped forward offering his penis in place of the dildo on the floor.  After he did it, he knew how stupid it was, that it would be found out.  He only hoped she did not notice immediately and he would have a few moments of sex with her before she did.

Alternatively he wakes up in the middle of the night.  Steps out to use the bathroom or maybe eat a little.  He passes the door to his mother's room.  Still open with the light on, but hears sounds of her sleep.  He steps in to turn off the light, the first time he had walked in the room while she slept since he was a little kid.  But then he sees her in bed, no blanket, either nude or underwear only, or other nightwear that stands out.  Again, he had never seen her like this before.  Other than swimsuits, nothing that showed off nearly so much.  He could not himself from approaching her bed.

That's the basic idea.  A happy conventional mother-son relationship twisted by one random night into something incestuous.  I want to play out the first night, using one of the above circumstances (willing to consider others) but then play out the aftermath.  See long term how their relationship shifts.