This LoRA is designed to aid in generating images of couples, usually in their underwear. Yes, I'm aware of addons like Latent Couple or Regional Prompter but not all generation services support them so you can try using this LoRA to help generate images of a man and a woman rather than getting two men or two women which most models tend to do out of the box.
There's no official trigger word but "man and woman" should work. Do not try to describe the man and the woman using tags - they'll bleed into each other. Instead, describe them in sentence form like in the sample images. You might be able to describe other aspects of the image using tags but if that causes the tags to bleed into the characters, then you might want to remove them.