I grabbed some of my homespun scraps. Flanell works, too, as any other lightly woven fabric, but my preference for rag quilts and chenille is homespun. With several layers of fabric flanell gets very heavy while homespuns still keep it light especially in a bigger size.
For my little try out sample I cut five squares of fabric, stacked them on top of each other and sewed a diagonal from one corner to the other. I kept sewing seams with 1/2 inches of the the previous one on each side of the diagonal all the way out to each corner.
After that step you cut in between all seams through the four top layers, just not the bottom one.
I used the Clover Slash Cutter instead of scissors for that step.
After all the cutting it went in the washing machine and dryer to fray and this step added all the softness to the fabric --------- chenille.