When I first started therapy I would do it all the time and usually for most of the session. In the end she encouraged me to really go into it and she taught me skills to ground myself so I could get out of it easier. I still do it now and she sometimes says to go with it and not fight it so much and wants to explore what exactly triggered it.
I know just what you mean about the whispering the need to stop. Mine is very good and stopping as soon as I get like that, and she rarely asks me how old I feel anymore as my responses can be a little rude.
Anyway I think what I am trying to tell you is that yes it is definitely getting better but that it has taken a lot of work to get it more under control. I wish you luck, I know it can be a tough place to be in, but remember it is a skill you have developed to keep you safe and help you manage some pretty awful stuff. It's not all bad.