https://civitai.com/models/74633 - This works with different models that output drawn images but I found AbyssOrangeMix3 (AOM3) works really good. It does not work at all with realistic images as no real images were included in the training data. use "pee stain" instead of "peeing self" if you want to ensure you get dark stains. Add more attention to "pee stain" for bigger pee stains. Add "pee" to the negative prompt if you want to reduce the copious amounts of pee that usually appear without removing the pee stain. Between 1 and 1.5 for the LORA weight will generate pee stains on clothing that previously wouldn't have pee stains, and makes the pee stains larger and more well defined. Be aware that changing the weight too much will completely change the image even if you use the same seed.