Depending on the model, you can provide various modifiers to get different results. The modifiers work best with the base SD 1.5 model. Photorealistic models will require you to adjust the weights to around 0.5. Other models may "override" how some words behave.
Version 1.0 was trained on 512x768 (portrait) images, so those will result in the best. Version 1.1 was trained on 768x768 images.
You can generate 768x512 (landscape), but you may encounter missing limbs, extra arms, and so on.
Example prompts
legspread a photo of a naked woman spreading her legs and showing off her pussy 👈 this is always a good starting point
legspread a photo of a naked woman spreading her legs and showing off her pussy (with labia)
legspread a photo of a (caucasian|black|whatever else) naked woman spreading her legs and showing off her pussy
legspread a photo of a naked woman spreading her legs and showing off her (shaved|trimmed|bushy) pussy
legspread a photo of a naked woman with (small|medium|large) breasts spreading her legs and showing off her pussy
legspread a photo of a (petite|curvy|thick) naked woman spreading her legs and showing off her pussy
legspread a photo of a naked woman with (fair|tan|olive|brown|chocolate) skin spreading her legs and showing off her pussy
legspread a photo of a naked woman spreading her legs and showing off her pussy (and asshole)
legspread a photo of a naked woman (propping herself up) spreading her legs and showing off her pussy 👈 I didn't have a lot of images for this one, but in the next version there will be
legspread a photo of a naked woman (with tan lines) spreading her legs and showing off her pussy
You can mix and match these modifiers how you see fit. You can put the other options in the negative to get a better result. No guarantees they'll always work!