New here, looking for some advice on getting bigger! 21F

Hello! First, some background info on me. Will put a TL;DR at the bottom if you don't for the nitty gritty!

I'm 5'10.5" (if that helps), and I've had an eating disorder (ARFID) for most of my life, I have a pretty damn fast metabolism, and I'm autistic. That combo of things has made it hard for me to gain weight and stop feeling like I'm a skeleton. Around 2023 I was ~120lb, and now I'm ~130lb, which is progress I'm still proud of!

I've always been a kinky person. I have a girlfriend who tends to indulge me, and I fool around with my friends somewhat often (with her being aware of this, obviously). Sometimes someone I'm messing around with will be into something I'm not, and I like to indulge them because there's a certain fun in fulfilling someone else's fantasy!

Turns out a good friend of mine is really, really into feedism. I started letting her stuff me when we're hanging out, and surprise surprise, I gradually got quite into it over the span of the last 2-3 months. Getting bigger, softer, rounder has been on my mind very consistently since then, and I've been trying to eat more to make that a reality. Might go without saying, but she's quite giddy about it.

I told my girlfriend that it's something I'm into the other day, and she's supportive of me in it, which I'm quite grateful for! I did not at all expect to find myself thinking about getting fatter this much. It's... a common thought these days. Wanting to get fatter feels embarrassing, but that just makes me want it more. My concern is that it took me 2 years of passively trying to gain to get up 10 pounds, and I'd rather be a little quicker than that!

TL;DR: The reason I'm here is because despite the attempts at gaining over the past two months or so, I've been fluctuating around ~130lb, no thanks to my high metabolism. I feel like my stomach has gotten a little bit more to grab, but it's hard for me to tell if that's placebo or not. I know progress isn't linear and that I'll probably get there eventually, but I was wondering what works for other people? Scrolling here I've heard a lot of talk of heavy cream and soda. I live with other people, so it'd be a little hard to hide anything in the kitchen that would raise any eyebrows. Happy to reply to questions and the like.

Excited to be here, hoping to have a reason to post again in the future!!