Basically, you dose the basket as usual and then do a normal straight tamp (doesn't need to be high pressure). You then roll the edge of the tamper around the inside lip of the basket - I looked it up and this is called a nutating motion (think how a coin rolls around its edge before it settles flat). Then polish the top with a rotating tamp motion, brush off any residue, and start the pour.
It seems to give a nice even pour, good crema and, if you drink ristretto, seems to accentuate the sweeter notes. It's also fixed a problem that I was having with uneven extractions (more coffee coming out of one spout than the other).
Interested to see if anyone else uses this or if you have a method that gives you a good result.
Edited by nickrey, 14 November 2011 - 10:27 PM.