It's a mystery.
Update - I found a .txt describing the training data and parameters.
Still haven't found the dataset, so I've added some recommendations, but use as a starting point with caution.
Trigger Tags; Teenie, BOP, TennieBOP
Common Tags; 1girl, solo, nipples, breasts, realistic, freckles, nude, brown hair, blue eyes, looking at viewer, small breasts, upper body, long hair, lips, smile, bent over, tanlines, leaning forward,
Starting Settings
Type: SDXL, Illustrious
Model: iLustMix
Steps: 18-40
CFG: 3.5-12.0
Sampler: Euler
Schedule: Normal
DISCLAIMER: All training data and datasets are synthetic. I have almost no idea what I'm doing with making LORAs, it's 90% trial and error, as such I make no promises about the results they return and warn that all may return unexpected results, all my models may return NSFW results. No likeness to real persons were used in training or are intended.