Gonna post a second one as well, this one being more of a "no shit, sherlock" one: Frankie Foster
>has a canonical scene in which she gorges herself on milk and cookies until her belly is massively distended, the former of which has high fat content and the latter being full of butter and sugar
>is addicted to said milk and cookies to such a degree that crackheads look like paragons of self-control in comparison, would absolutely eat them and nothing else 24/7/365 if given the opportunity, thereby gaining a shitload of weight rapidly
>not super-fond of her job as nanny+caretaker, would slack off if she ever got the chance, especially if it involves eating more of the above
>evidently gets no action whatsoever, higher likelihood to try some kinky shit by herself as a stress-reliever, only to get way too into it when it gets her off
Frankie seems like the kind of gal who'd go through life into her late 20s - early 30s without any real notable kinks, then pack on enough weight to get a bit chubby via a mix of stress-eating, aging and caring less about finding a partner over time. From there, she'd find out suddenly one fateful late night while self-pleasuring that she kind of likes how being doughy feels, and let it slide a bit from then on. Couple more pounds here and there end up feeling even hotter, and before she realizes what's happening, she's become a bonafide fatty who's turned on by her own girth. Not a huge leap for her to get even bigger after that, especially if it gets her hot and bothered.
Alternatively, she somehow gets easy access to a fuckton of milk and cookies without anything strong enough to snap her out of her obsession and pull her away from them getting in the way, and rapidly balloons in size thanks to a regular intake of high-fat and high-sugar food and drink. Going off of her impressive stomach capacity and her all-consuming addiction that fully occupies her mind when triggered, she'd probably gain at a record pace and keep growing nonstop for as long as the cookie and milk supply was kept up, possibly to SSBBW and even immobile sizes.
Either way, Frankie seems like it makes more sense for her to be soft and squishy to some degree, rather than stick-thin as she is in the show. I have never once in my life seen a woman eat like she does and not be at least pudgy, and usually they're quite a bit bigger than that. Some women seem hardcoded to be gluttonous and fat, and she fits the bill too in my opinion.