I'd say standing up and focusing on putting your weight on your rear pedal will help keep you under that out of control spin. But as said above, skips and seated skids are the most controlled on a decent. I think that learning to descend very fast but being able to stop when needed is a very important skill, I often will practice by bombing a hill and choosing a spot to start an attempt to stop and work on how long it take to do so. until you get it though just use that brake