This lora provides a better depiction of a nude woman as viewed from behind.

Include something about revealing or exposing or showing "vulva and anus" in your prompts. Something about "facing away" from the camera helps with positioning. Specify clothes (or lack thereof). Stuff like "hips raised", "on hands and knees", "squatting", "kneeling" really anything works if you can get the model to put the woman in a favorable position. And "head turned to side" helps if you want her face in the image. Can try stuff like "grabbing butt with one hand" but more challenging to get right. Can generally set at 1.0 strength, sometimes a bit lower helps if you want a more subtle effect.

I tried to choose a happy medium between accuracy and adaptability. Works pretty well with closeup views, clothing, character loras. Not great with pubic hair though, perhaps in a future version.