The assumption is true for me.
I would usually look for certain topics or motives relating to my fantasies. I sometimes find stories matching my fantasies to a certain extent but then I'm sometimes disappointed.
On the one hand my own story matches my fantasy only limitted by my (lack of) ability to narrate, on the other hand the story and its punchline is predictable and promises no surprises.
Assumed reading porn makes you horny:
Would you ever (or did you) jerk off/touch yourself over your own story?