This LoRA should help to achieve the double penetration position of the frontal and on back type. The girl is sitting upright (or leaning back) on top of a man who is fucking her ass whilst the other man standing is fucking her pussy.

It was trained with base SD 1.5 for wider compatibility across models, but might not work well on some models. (Works with more models, but might not work very well compared to training it for a particular model.) Training set was real photos with a range of different women.

Trigger words:
dpfr
dpfr, double penetration

Prompt style that might be effective:
dpfr, double penetration, <description of woman>, spread legs, 2boys, penis, multiple penises, testicles, mmf threesome

Higher epochs might be more effective on stubborn models.