I don't really have a journal, but my Master wanted me to write fantasies for him, so I have a little book of them. Sometimes I write things that I like, sometimes things that I think he would like, and sometimes they are the same things because there is a lot of overlap. Some types of things I write: describing actual sessions that we've already done together and really liked, pure fantasy set in another world with other rules, fictional scenes set in our society, or describing a session between us that I'd like to try (those are the hardest).
Last night he held up the little notebook and said it was the best book he ever bought, which was amazing to me and felt so good. I'm not a great writer, or a professional writer. It's even harder for me to tell fantasies out loud than to write them, but he always wants me to do that too. I'm easily embarrassed by some of my fantasies. I'm even more embarrassed that one time I got so disgusted I ripped out half the pages from the journal and threw them out. Boy was he mad. I won't do that again no matter how lousy the story seems later on.
Most of my fantasies are things I wouldn't really want to do.