I've been rattling around the idea of a long form mom-son vore story in my head for a while that I want to run by you guys and see if it would be worth writing. It's anthro shit so if that's not your jam, please disregard
The premise is a mom and son shark anthros, the son who had moved out has to move back in with his mom (dad completely out of the scene, left/died when he was a kid), through the magic of smut writing they start up am incestuous sexual relationship. In this setting there is some explanation for random shrinking occurrences to happen. Shrink virus, weird space radiation, whatever. The son catches the shrinks much to his mother's dismay at first but her overprotectiveness ends up leading to shrunk related sexual shenanigans. During one instance of getting things on, the son mentions he wants to cum in his mom's mouth with ends with him precariously standing on her lip as her opens wide while he jacks off into her maw. This goes on for some time until wanting to cum in her mouth turns into him braving her maw to cum IN her mouth, with a jokes being made about cumming straight down her throat. The mother jokingly warns him not to slip as she has no gag reflex but at the time isn't entertaining any vorish thoughts, but this event sort of triggers them. She starts pushing the limits of their situation, teasing him in the tub, jokingly referring to him as a snack, etc. This comes to a head one night over a steak dinner when she brings up the dangers of her throat for her son to say she probably couldn't even swallow him if she tried. She sizes him up and proceeds to cut a piece of steak approximately the same size and swallows it whole albeit with some effort, supposedly just to prove him wrong but secretly to see if she actually could. At this point she's basically decided he's going to end up in her tummy at some point but still has those motherly I can't eat my son thoughts, only their not strong enough to outweigh her newly developed kink.
More sex, more mouth play, more teasing to the point where while he's in her mouth, she'll move her tongue secretly hoping he'll slip and give her an excuse to accidentally swallow. It gets to the point where she finally comes clean and admits ever since the steak night she's fantasized about gulping him down. The son doesn't take her seriously thinking it just another layer of teasing but she eggs him on, talking about how much she wants to feel him slide down her throat. This goes on until one night when she's finally reached her breaking point, when she's got herself worked up in the heat of passion, she tells herself she can't stand it anymore and wants him in her. He finally realizes she's serious and tries to convince her not to go through with it and she agrees that it he can hold on to the tip of her tail dangling over her mouth until she gets herself off, she won't eat him, but if he slips of let's go he's going to take a one way trip down her throat. Sure enough he slips and after some near miss mouth play thinks she might not intend to swallow him after all, and while she does debate it one last time, as soon as she cums she gives in. The son is snacked and she is double aroused at being able to feel and hear him inside her stomach. She continues to jill and sort of tell herself once she's done she'll let him out, he's her son and she shouldn't really eat him, but by the time she's done she's fully given in and the son has accepted there's nothing he can do about it.