Pretty good like always

Excellent work

The prose is amusing in places and the vore is good. I’m all about soft and happy swallowing. However, this could really use some world-building. The best approach would be to get away from the royals, follow an ordinary human living what passes for a humdrum life, and just keep asking questions. What’s his or her job? When he walks down the street when some people are cranky in the morning, how is he greeted? What are his relationships like? Regarding housing, is there a human district in town, are their houses evenly interspersed to symbolize full integration, or does their pet status mean they have to live with pony owners? What’s it like for a human married couple living with kids? How do those kids fit in the school system? Are humans basically just pampered slaves with no real rights, or is it more like a caste system where humans are expected to live up to the role they’re born into?

Gabe called Celestia his mom, yet he’s a pet. If Twilight’s parents had a pet human, how would that human relate to Twilight and Shining? If it were me, a dude coming out of a girl's ass would have a lot more detail and be overtly sexualized, so this would be rated M. Looking back you also mentioned wombs, which would absolutely call for lewd detail. I don’t recall how clothing fit in the previous chapters, but the lack of mention here implies that Gabe and Celestia have no scruples about him being naked all the time. Are humans as naked as ponies, wearing clothing only for special occasions? Again, if this were me, it’d be rated M to more thoroughly explore the lewder side of things. For example, a married human couple and pony couple basically being a foursome and regarding one another’s children as their own.

Another interesting avenue might be exploring the darker side of things, like what happens when a human and pony don’t get along. Was the human sold to a bad owner, whose friends then pressure them to rehome said human? Is mistreating a human frowned upon, but legal? What happens when ponies dislike how humans are treated, or even has some prejudice against them and believes they should be put in their place? How do consent laws apply? This goes back to the housing issue, but is there a foster system similar to dogs? Are humans given away as soon as they’re old enough? If so, how do the parents react? What happens if a human just doesn’t like being eaten and violently resists? Are there wild humans who live away from ponies and sneer at the pet lifestyle?

Glancing back, Cadence and Shining don’t have much of a relationship. Does he have his own human? If humans can also go into wombs, does this extend to penises? Is it a pressing social issue that ponies prefer humans over each other? Or, at least, is that something that some ponies are voicing concern over? Also looking back, it seems that humans really are just pets to be bought and sold, so that answers a few questions. Regardless, a solution to the problem in chapter 3 would be to institute breeding programs, increasing supply to lower costs. What would it be like for humans in such programs? And since there’s prejudice toward humans stemming from rumors, that just makes things even more interesting.

I’d explore lore by starting with a day in the life. As mentioned, get away from royalty, so follow the routine of a human belonging to someone in Ponyville besides Twilight. I’d also avoid Fluttershy since she’s an animal lover and therefore, using her kind of feels cheap. Maybe you should go with someone older and more self-sufficient who can work a real job, and preferably a woman for the sake of diversity. The last few chapters have all been young boys, so you need variance. They wake up, get affectionate with their owner, and just follow them around town just living their life, interacting with others, and simply observing things around town while making mental commentary. You can get a lot of world building from just giving an ordinary person’s opinion on their surroundings.

Applefai asked for lore suggestions on your behalf, so I hope this helps.