Chasing The Idea Or Fantasy

Have you ever had a thought like an sexual idea that could be possibly possible. Or is it an actual fantasy that you want and desire?

I find it hard to pick between the two because an idea sexually is just a thought that I would say make me feel unsure about my actions and choices.

Where if it's a fantasy I would want to masturbate with the desire to want that feeling that touch that connection of being abel to just be completely comfortable with yourself and the other in moment.

So I'm confused between Ideas And Fantasy?

What's your opinion