Here's Liz demoing the Spin Stop. (To re-run, double-click on the image.)
Clip 1: I shift 2/3 of my weight to my right skate and steer it into a turn.
Clip 2: Pivoting on my left toe wheel adds support and keeps my weight centered.
Clip 3: My heel touches down right away so I can spin with weight on both skates.
More details in the Advanced Stopping Orbit article.