Can anyone remember who did the original tufted pillow technique on this site?
Some of you managed to figure out that it was rectangles cut out and pinched at the ends, you could either pipe buttercream or use mini marshmallows to help it hold its shape
It has disappeared from my favorites.
It's called billowing, that may help with your searches.
You might try" dabear" (s)he had a beautiful cake picture posted or the joyofcake.shutterfly.com has a tutorial.