This is my wetting LORA trained on 100 images from Gelbooru. It focuses on wetting and can do dark stains. There are no activation words. This works with different models that output drawn images but I found AbyssOrangeMix3 (AOM3) and RevAnimated works really good. It does not work at all with photos as no real images were included in the training data.
For Version 1.0 use "Peeing self" to make sure the image include the character peeing themselves.
For Version 2.0 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.
After some more testing I've found 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.