The time scale is a little hard to pin down, but a few things certainly come to mind.
I remember stuffing pillows and other such things under my clothes from a very young age. I eventually had an entire process, using almost every pillow and blanket in the house, nearly every article of clothing in my drawers and closet, and a pair of my Dad’s one-piece long johns.
I do remember before that putting on my out-grown clothes and trying to pop the buttons on them, generally while fake-failing exercise, and that one I can actually pin down. It was an old Goofy cartoon, of all damn things. Goofy had gotten really fat, and his reflection in the mirror was mocking him. “If you can’t see your toes, you obviously can’t touch them.” And of course, he bent over, popped all his buttons, and failed to touch his toes.
Honestly, that one sequence inspired a whole lot of fetishes, lol.
The final thing that pushed me over the edge was a poorly monitored internet connection in the glory days of dial-up. I found the Dimensions website, and found a couple things that sold me on this kink for life.
One was the model kelligrl. She’s been retired from the scene for quite a while, quite possibly before I even found her, but she was legendary. You can still find her photos and videos online. At her biggest, she was stated to be over 500 and gaining, although I don’t know if there was any formal confirmation of that number. She was quite unique in that, despite her considerable girth, she didn’t gain any weight in her face. Her cheeks may have rounded out the barest amount, but if you saw her from the neck up, you wouldn’t have guessed she was as big as she was.
I suspect her rather rare weight gain appearance is the main reason I’m not too enamored with a fat face. Some are fine, others are gorgeous, but many just don’t look good to me.
The other part of the site that I put far too much time into was the weight gain fiction section. The “I Hate My Twin” series by Zarbon was unquestionably my favourite. Part 8 of that story, in particular, I’ve read dozens of times over the years. And while I’m not as fascinated with immobility as I once was, I still like playing around with the fetish now and again, and I can trace that straight to Zarbon’s creation.
The combination of the two things, thin face yet being an immobile fatty, was undoubtedly what drew me to Foxfire’s OC, Kiari.
So yeah, a few things certainly come to mind.