This is a great idea. I tend to do this myself, I usually type up a message on my computer, as if I am going to email it to my T, telling her how I feel, letting out the feelings etc but then I just save it to my computer and don't send it. I usually go back to it a few times over the following day or two and add things, delete other parts and save it again. It's only if I still feel the real need to share it with T after this that I do, but usually the release I have gotten from writting it all out is enough.

It's a great idea and I hope it helps you a lot!