https://literotica.com/s/moms-post-apocalyptic-debauchery
Haven't read the whole thing yet but I like this guy's work, the writing could be better but he approaches the genre with some wacky ideas which is right up my alley.
This is a good story, you can change the subject as an option, for example, go to an exotic country, remove religious overtones, for example, the family must go through various rituals where the mother will be prey, and the son and father must look at all sorts of things.
You can draw inspiration from various films about exploitation, cannibal tribes, but I don't think you need to include bloody violence, carnage, rather just a fun adventure, but take away, leave purely sexual things, you can do scenes in which a mother undresses in front of her son and father, say, she has to teach the teenagers of the tribe sex, So the action will take place for several days, and every day will be worse if, say, first she just undresses, gropes, then you can leave the invention of various sexual manipulations
You could make a happy ending with an escape at the end, let's say the mother did all this to save the family, but she would be terribly ashamed to admit that she liked it, and in a conversation with her son she would admit how much she liked it.
You could remove the father completely to create a composition and then focus on the two characters as if it were a pure NTR mom theme.
p.s. I just came up with this idea when I read this story ahah, I translated your message incorrectly, I thought you were looking for inspiration, but since I drew this, there is a concept here.
p.s P.S it seems to me that the idea of using the image of stars, pornstars, is generally insanely cool, it is unrealistically exciting, as soon as you see this woman, there are such juicy women as Kelly Brook, Sofia Vergara, Jennifer Connelly, they are insanely sexy, but even Julia Ann has already created many images in this story, but the story itself is certainly kitschy on purpose, which is also not bad.
As soon as I have time, I'll try to find a couple of interesting stories, I'll just have to sit in the archives.