Ah, thought this was in NovelAI. Wasnt even aware of Cmdr2 GUI's existence, but a quick look shows me its of a seemingly weaker model, and a rather lacking UI.
It took me ten attempts to make this with NovelAI's model, using the initial image you posted as the base.
For NovelAI Strength controls how much the uploaded image is altered, so its the equivalent of the Guidance setting.
Noise is the fancy setting for adding detail to an image, but its real fucking finicky so you have to tweak it a lot.
Prompt strength in NovelAI is Scale, which i set to 7 for this image.
Prompt Used: "A blond haired young man ripping the clothes off a pretty girl, {by Diego Velasquez}, nsfw, detailed"
Strength: 0.4
Noise: 0.05
Steps: 50 (default)
Scale: 7
Edit: I tried about 200ish more attempts at this and I can confidently say, that stablediffusion was not trained on enough images of this format to make anything more then passable images. You'd have to also edit these images substantially to aid the AI in creating this prompt.
Cmdr2 GUi is, well, just a GUI for SD (the good: one-click install, support for legacy hardware out of the box and a detailed styles GUI, plus the guy is always very nice and helpful. The bad: it's a rather weak and very barebones GUI and img2img in particular sucks great time - I installed Auto's WebUI at work and it's a lot more professional).
The models are whatever you put in: I'm mostly using a blend of f111 with pretty much everything else, that I found on the Unstable Diffusion Discord.
f111_0.4-NAI_0.25-gg1342_0.125-r34_e4_0.125
I never tried pure NAI: from what I gathered, as most NSFW models around, it's focused on Anime/Manga look, and I'm simply not interested in that style.
While I plaud your result as a great achievement on the road of lewdness, it's well... Anime.
Currently, I'm experimenting wildly to understand what causes the style transfer to trigger. Sometimes the AI gives me a batch in renaissance-style (not baroque, but hey, one has to be realistic about these things) with an initial image and a modern-looking batch with prompt-only (exactly the same prompt), sometimes it does the opposite.
I think bright, contrasted images force the modern look and that Prompt Strength and Guidance Scale don't have much of a word in it.
I also suspect long prompts are more likely to ignore the style.
Since I'm on CPU-only, due to my GT730, in this format an image takes several minutes (my beloved 512x256 format doesn't work for NSFW), so I can't really go full scientific in this research.
Also, GFPGAN doesn't run on my home computer: that one would've helped with small faces like those.
Raising steps beyond 20 didn't make any difference for me.
You have one more parameter than I have:
Strength -> Prompt Strenght
Scale -> Guidance Scale
Noise -> -
I'm going to ask some questions in the GUI discord...
I fully and heartly agree with you: humankind needs more NSFW training. Especially for group sex: when I try groups I mostly get sequels of Carpenter's Thing.
P.S.
I can't believe I didn't save the prompt.
It was something like (young blond man) ripping the clothes of a (pretty) girl, with (perky tits), nipples, ((beautiful face)) in a warehouse
P.P.S.
I just finished downloading a f222 blend.
This is its take on the task (Scale 4, Strenght 0.4, 20 steps):
style: detailed and intricate, pastel drawn art, by Caravaggio