mollydc:
I have never done anything like that since. But I can't help but obsess about if it means I was a terrible person!
This really stuck out to me because I can understand why you'd wonder that, but as someone who also had childhood versions of feedist experiences, I can at least share my insight on this.
I didn't identify my feelings as being an actual fetish until I was almost 20, and then it intensified the scope of my sexual fantasies, which had always been about growing bellies and fattening up. It freaked me out, but over the years I had no choice but to engage with it because this is what gets me off.
At 29 I decided to gain weight and find a relationship with a man who was compatible with my fetish, and at this point I'm 100% happy with it on all fronts. But in the interim I had a series of awkward fantasies based on things from my childhood. Those were replaced as I had real life experiences or found new fantasies inspired by stories and people documenting weight gain in pictures. What I'm saying is: just because something that arouses you includes a sibling in childhood does not mean you are sexualising a child - it is completely possible to view a sexual memory from a childhood perspective, and it doesn't sound like the experience was sexualised on her end. Just because you experienced it that way does not mean that she did, as a fetish is by definition the sexualisation of something that is not sexual in origin. (I'll leave the philosophical side of that debate for others, though!)
My advice is to keep thinking and feeling your way through it, and as you become better acquainted with yourself and whatever it is you find yourself desiring, I think you'll find that these fantasies will become a distant memory as you develop a more enjoyable selection from your wank bank

Best of luck!