Winter has some tips for what to "think" of instead--and remember, you're holding this for 10 seconds straight:

First, we want you to fantasize that it is a warm spring day and you are lying in the bottom of a canoe on a very serene lake. You are looking up at a blue sky with lazy, floating clouds. Do not allow any other thought to creep in. Just concentrate on this picture and keep foreign thoughts out, particularly thoughts with any movement or motion involved. Hold this picture and enjoy it for 10 seconds.