Activation text is: yumemizukimizuki
Her default outfit can appear with varying results using: defaultoutfit
If you want to make it more likely her tail appears, add: demon tail
To get her swirly eyes, you can try running an inpaint with ADetailer and the following prompt: purple pupils, (@ @:1.5)
Recommended to add to negative prompt: black pupils
Bonus! You can summon companions adding this to the positive prompt: yumekui-baku
In my experiments, the best Weight has been 0.8, YMMV depending on the checkpoints you use. For compatible checkpoints and example prompts, please check the sample images.
Let me know in the comments if you like it, I might try to improve it in the future.