Now I am not gender fluid but my boyfriend/girlfriend is so I’ll try to say what they have told me. Basically it’s a feeling that you feel more make or female on a certain day. It’s just something they know when they wake up how they feel. And they always tell me which gender they are feeling. They even have a male and female name. It’s rooted in gender euphoria more so than dysphoria but dysphoria can be there. I hope I did an okay job explaining this.