Folding a stuffing technique varies with the density of the flake but essential i fold a flake in half across its length, than again across its width. the flake is than rolled between the fingers to lossen it up and put in the pipe. You need to be careful that you're not wedging it in at the sides of the bowl it should set in easily. you also want to judge howl much you'll need so that it isn't towering out of the bowl. I than use my thumb to gently rub around the top of the tobacco to provide an even lighting surface. I keep a square of leather at my desk that I fold my flakes over, a paper towel works well, to catch the crumbs. I use the crumbs over the top to act as a bit of kindling. The problem you describe could come from not loosening the flake enough before stuffing, or stuffing too tightly. There is a video posted in the GE sticky that shows this probably better than I can put to words.
Bearing the burden of responsibility..... It's probably my fault.
Treat your silver as if it were earthenware and your earthenware as if it were silver - Seneca, Letters of a Stoic