Please describe exactly what you want, because a bookmark that moves is not a bookmark, and it is probably very obvious in your head but reading your sentence makes no sense at all in my head.

With a paper book, you pick it up, open it to the page where you put your bookmark, set the bookmark on the table, read for a while, and when you're done you replace the bookmark at the location where you stopped reading, not where it was initially when you picked up the book. In other words, you can move the bookmark. 

Okular, on the other hand, always keeps the bookmark at its initial spot. You have to manually delete it and add a new bookmark when you finish reading so you can find your spot the next time. This isn't a big problem when you're only reading in one spot per file, since Okular remembers your current location. But it can be very troublesome when you are reading in several different locations concurrently (e.g., when you're reading two stories at once).

I would like an option to create dynamic bookmarks that update themselves each time you scroll forward or backward one page at a time. Not more than one page at a time, because I don't want the bookmark to update itself when I manually skip to a random page, nor when I switch pages using another method, such as clicking on the Contents tab or selecting another bookmark. Only when I scroll forward or backward.

Ok, much better now, i don't think this will ever happen, but will leave the wish open in case a majority of users decide to vote for it