Two heads are better than one!
Trained on URPM 1.3, use that model for best result. But it works quite well with other models.
Recommended weight: 1.0-1.3
For best result prompt with the following structure:
<style> of 2heads, woman, <framing of picture>, <actions>, <skin color/race>, <hair>, <other details of subject>, <clothes>, <background>
Works surprisingly well on a wide variety of styles, even non photorealistic ones.
Hi-rez fix recommended.
Also if you pose the subject in the center you can use latent couple webui extension to give additional prompts to the two sides of the image so you can make each head have different expression or hair color.
For three breasts you can use tribreasts, double cleavage tags. If you don't like them put it in negative prompt as it will sometimes generate it like that without those prompts.