Try this.

Get in a place where there is no distractions. Turn off TV, music, whatever. Put two pieces of paper on a table or desk. Close your eyes, take a couple real deep breaths and then open your eyes and write the first thing that comes to mind on one piece of paper. Answer it on the other piece. Go back and forth about whatever comes out.
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Example
Paper 1-------------------------------------- Paper 2
this is stupid ----------------------------------yeah, some idiot on PC suggested this
how will this help me in therapy -----------------who knows
i am getting angry at this exercise -------------- i always feel angry

Good luck.