I think Wendi Deng was probably free writing when she wrote how much Tony Blair's physique delighted her. Her note ending "and what else and what else and what else..." illustrates a technique that keeps the pen flowing across the page by writing the same thing over again until something else comes up.
For free writing forget about punctuation, spelling and sense. Just let the pen flow. Disengage your mind too. Try not to think what it is you're writing about.
Sometimes after I've been free writing I can barely read back what I've written as the words flow into one long line across the page. You don't need to read it back anyway. It's the process that's useful for freeing up words.
Afterwards you can throw your free-writing away, put it under your pillow or save it to look at for another day. Although, if you do this you might want to make sure no-one else reads it (Wendi take note!)
If you do read it back what you see may surprise you and you may have no memory of writing it. Free writing comes from the unconscious and can lead to insights and material for further writing. Peter Elbow advocates free writing for at least 15 minutes a day to find your voice and to get rid of the inner editor.
At the recent London Lapidus workshops Helen Beale, who specialises in somatic writing, suggested we free write for 5 minutes and then underline all the words and phrases that stood out to us. She then asked us to free write for another 5 minutes incorporating as many of these as we could. We repeated the process a third time. Helen says the first 5 minutes writing is often what she calls 'froth', the next more intense writing and finally the last 5 minutes is about expansion and release.
To finish the process, Helen suggested we make a poem or short piece of writing using the words and phrases we chose from the final free write.