I'm close in raising my serpent as well. I don't really know what stage I'm in but I know that I'm close if I meditate long enough and enough times a day (I usually go for about 15 minutes, 3 times a day) and I've been told that you will know when you're fully raised.
You might experience a sense of intuition and knowledge beyond anything you can imagine. Your view of reality may change as mine did (and I think i'm going a little mad here).