Pony:
I did a lot of ai stuff a couple years ago, just SD1.5; I took a break when XL was just coming out. I recently got back into it a month or so after Flux was released. So I didn't do much with XL/Pony/Illustrious/etc because of that gap time. Just getting into Pony now and am super impressed with its trainability with sex positions/acts. It doesn't hold a candle to Flux in terms of realism or face accuracy, but hot damn is it easy to replicate the most deviant of carnal acts!
Flux:
Not gonna lie, it can throw a lot of mutations your way, but you do get the occasional gem. I trained this one on Civitai instead of locally, so maybe I'll try again for a longer amount or look for more/better pics for the dataset.
Adding a dick LoRA or using one of my other models, Jerking Off Watching, seemed to help. But I think the best results I got were from adding a little of the LoRA NSFW_Master to it. See below in the recommended section.
It is also resistant to showing faces, though it's possible, but I outpainted the faces in the examples. Original and outpainted versions are included so the metadata can be used.
For free DL:
Flux: https://civitai.com/models/1050123?modelVersionId=1178325
Pony: https://civitai.com/models/1050123/standing-pussyjob-or-jerking-off-into-panties-or-flux-pony