https://civitai.com/models/11126/pant-pull-down-lora
General Prompt Guide
Simply add pantpulldown towards the end of your prompt, followed by lora:pantpulldown:1
Add "rear view" angles towards the beginning of the prompt: rear angle, from behind, viewed from behind, back towards viewer, ect..
Noting the butt size somewhere in the prompt can also help: big butt seems to work well, but can sometimes force closeup shots.
Adding full body towards the beginning is useful for full body shots. (note, this may be different depending on what SD model you use).
For short length prompts setting the weight between 0.5 and 0.8 seems be optimal: lora:pantpulldown:0.6
Conversely, For longer length prompts setting the weight to 0.8 and 1 seems to optimal: lora:pantpulldown:1
Describing whether or not genitals are exposed can help elevate issues where genitals are not generated properly, or are visible when you prefer they not be.
Interestingly, I've had the best results by adding the LoRA at the end of full length prompts; as show in most of the sample images.
Issues
Bad faces
Try adding "pretty face" to your positive prompt.
Bad hands
Hands are the devil for Diffusion models; try adding "perfect hands" to your positive prompt, and "mutated hands, distorted hands", ect.. to your negative prompt.
Bare bottom with no pants
Increase the LoRA weight in your prompt.
Realistically, A hypernetwork + still frames of people undressing their pants would likely be ideal. This is something I'll consider after I finish training my upcoming "Enhanced skin texture" hypernetwork.