Here's how you do it:
When you get frozen, wiggle like a mofo.
When you see an attack coming at you (6C especially, since there are only a few freezes that guaranty it) stop wiggling and hold 1 down, regardless of wether you think you wiggled out or nor. Why? Because if you continue wiggling when you have broken out you eat a combo, and if you haven't broken out it's too late and you should stop anyways. (if it's overhead go to 1 then 4, so you don't BD and get owned for it.)
Also, always wiggle between 3 and 1, it stops you from backdashing like a tard when you wiggle out. Plus it's actually faster to do it that way on a pad for you pad warriors out there; the distance is much shorter.