Dear cadillac owner,
I’m of the opinion that there’s no hard and fast rules on this matter. My advice is to employ some of that good old fashioned intuition that we’re all born with, reach down the crevasse in the cushioning to where the solid fixture is, grasp it and give it one sharp pull, followed by a series of longer yanking motions until the whole thing starts to come away.
And voila! DIY self-propelled rocket artillery: Get out of my dreams, Get into my Car. Get in the back seat baby.