I did try two attempts of it as a concept lora. Largely didn't work out yet so far. I did have some generations that looked likely what a person would want with that but it was extremely random and very temperamental. It does seem like an interesting concept to make, but I think the checkpoints usually override it since they seem more build on generally having cropped or generic men. I'll keep trying, but I'd say don't have high hopes for it. I'll likely have to browse rule34 a lot for it for 'viable' high quality images, as doing a generic 'top 300 images of highest score' clearly doesn't work for femboy_on_female doesn't work at all.

https://civitai.com/models/966350?modelVersionId=1081961 Promises made, promises kept.