Here is a nice video showing Skagit style Spey casting. Skagit Spey is one of the three predominant style in Spey casting. The other two being traditional mid-long belly Spey and Scandinavian Spey. Skagit and Scandinavian (Scandi) Spey casting are also sometimes referred to as shooting Spey because of the use of short shooting head (20ft - 35ft) and thin running line to achieve distance. Because of the shorter head, the D-loop of these two styles are by design smaller than traditional Spey and therefor require less back cast room to execute.
While traditional Spey and Scandi Spey predominantly make use of touch-n-go or kiss-n-go anchoring, Skagit Spey make use of sustain anchor almost exclusively. As the name implies, touch-n-go anchor is set as the leader/fly momentarily touches the water. As for sustain anchor, sink-tip/leader/fly is allowed to sit on or sink into the water column long enough to provide a good grip for the anchor.