What AI are yall using to morph girls? I would like to do some myself

Looks like some people are doing Photoshop copy and pastes from random stock of bellies / warping the original photograph. This is the old way and can look good but relies on a bit of luck for the right pose from the source and target photograph. Also it's easy to set up Photoshop or GIMP and get started this way, but the skillset is insane and the best of these morphs are probably done by wizards who have spent > 10,000 hours in Photoshop.

The newer method that you're talking about is Stable Diffusion inpainting using a LORA like this:

https://civitai.com/models/111172/realistic-pregnancy

Stable Diffusion can be daunting to get started with (even the initial setup) but you can start getting results pretty quickly if you stick with it. I recommend checking out Stability Matrix which is sort of a launcher that handles the installation and then helps you to you manage the various extensions.

Worth mentioning that you need a beefy system to run this software locally. Your other option is to run it through Google Colab which you can learn about here: stable_diffusion.ipynb - Colaboratory (google.com)

I'm only getting started with SD and I too would love any sort of advice from the people here working with it.