https://civitai.com/models/858437/lesbian-fisting-lora-for-pony

You can use this LoRA with a recommended strength of 0.9. Should work with different Pony based models.

rigger prompt: fisting

Try to use the trigger prompt like this: (fisting:1.8)

Giving it such heavy weight, forces the LoRA to produce more accurate fisting. You can combine it with the prompt (yuri), to make sure the LoRA understands that it is about displaying lesbian love.

Here is an example for my prompting:

positive prompt 1:

(score_9, score_8_up, score_7_up, rating explicit, (realistic:1.9), best quality, ultra HD quality details, cinematic film still, volumetric lighting:1.9, blurry background, shadows, full body shot, from above), (1girl, 26 years old, nude, head tilt, looking at viewer, smile), (fisting:1.8), (yuri), (skinny:1.6), (big breast:1.2), (nipples, detailed skin, dark tanned skin:1.6, tan lines, black long open hair), (indoors, bedroom, bed, window, garden, blue sky, clouds, sunny day)

positive prompt 2:

(score_9, score_8_up, score_7_up, rating explicit, (realistic:1.9), best quality, ultra HD quality details, cinematic film still, volumetric lighting:1.9, blurry background, shadows, full body shot, from above), (1girl, 22 years old, nude, sitting, hand on stomach, feet up, legs spread wide open, looking at another), (fisting), (yuri), (skinny:1.4), (big breast:1.3), (big labia, detailed skin, navel, nipples, tanned skin, tan lines, blonde long hair), (indoors, bedroom, bed, window, garden, blue sky, clouds, sunny day)

negative prompt:

four fingers, six fingers, six toes, four toes, multiple nipples, ponytail, saliva, dripping, tattoo, short hair, logo

Do not expect perfect results, be aware of that! If you want to get more stable and controlled results, you have to use inpainting. But as far as using a LoRA ... this works "fine".