I only just got this move recently and I have been poling for nearly a year and a half! I never felt secure enough to actually lay back in it, and any time I did try (with a spotter or mats of course) i would slide right down to the ground. I had only ever held it for a split second by going into it from a handstand, and immediately proceeded to slide right down again. LOL
I had heard a lot of people say that the planks (particularly the advanced version, with your hand underneath you) are much easier to learn once you can do the CAR and since I couldn't CAR I had never really put much effort into them. Well, I finally got fed up with trying and trying and trying and failing miserably no matter what I did, I had tried every tip I had ever heard; turning knees in, turning knees out, squeezing bum, etc. and had absolutely no luck. I decided that it was going to be a move that just wasn't going to be mine but I decided, well what the hell maybe I can learn that damn advanced plank anyway. Everyone kept telling me to get the CAR first, but I decided to go at it my way. After a couple practices I nailed the basic plank (I had done that one before but never put any time into learning it nicely) and could do a rough advanced plank, not necessarily pretty getting into it, and couldn't hold it long but you get the idea. Then one day in an advanced plank moment that felt pretty secure I had the thought to tilt my legs up and try to walk my hands down lower and give the old CAR another go...and whaddya know? I did it! Not only did I actually hold the pose, I didn't get into it from a handstand (which I always though would be easier) I did the layback part too! And then I thought, this is great...but can I get back up? Sure enough I even pulled myself back up into a pole sit. In that practice I completed the layback twice and pulled myself up twice (with one attempt failing miserably in between LOL). Just goes to show that sometimes move progression is different for different people!
So my advice is to just forget about the CAR for awhile, don't even think about it. Work on those planks and one day it will just feel right to try it again, and it will happen! <3 <3 <3 Good Luck!