See, personally I'd rather see something where that is done more realistically. Bully beats up son & ties and blindfolds him. Mom then fucks the bully instead of helping her son. Achieves the same sort of scene, but in a more down-to-earth way.
Several such scenarios can be banked upon.
Long winded stories which focus more on the mother's slow and gradual corruption are the most erotic according to me.
I don't know why someone hasn't written any stories based on real life Misty Vonage and her son.
She cuckolded her son like anything.
Any story from that pov of watching your mothet enjoying getting dicked down scene after scene and enjoying the debauchery and humiliation of the son, will be an instant turn-on for everyone in this forum.