A weeks ago I was reading the book "Feeling Good - The new mood therapy" by David D. Burns. It is a self-help book about dealing with depression using cbt techniques. I came upon this paragraph:
"Mental Biofeedback. A second method which can be very useful involves monitoring your negative thoughts with a wrist counter. You can buy one at a sporting-goods store or a golf shop; it looks like a wristwatch, is inexpensive, and every time you push the button, the number changes on the dial.
Click the button each time a negative thought about yourself crosses your mind; be on the constant alert for such thoughts. At the end of the day, note your daily total score and write it down in a log book. At first you will notice that the number increases; this will continue for several days as you get better and better at identifying your critical thoughts. Soon you will begin to notice that the daily total reaches a plateau for a week to ten days, and then it will begin to go down. This indicates that your harmful thoughts are diminishing and that you are getting better. This approach usually requires three weeks.
It is not known with certainty why such a simple technique works so well, but systematic self-monitoring frequently helps develop increased self-control. As you learn to stop haranguing yourself, you will begin to feel much better."
I wondered if something like this could help me fight DDing too. So I would click the counter everytime I caught myself daydreaming along with describing the thoughts in my notebook. It might be too early to say but it is kind of working :)