I use fleece. 2 1/2 to 2 3/4 yard of fleece. Trim the sides.
figure out my pillow.
I have crocheted around the edges. I put the hole in using
Skip-stitch (perforating Rotary blade. Medium. Fits a 45mm rotary cutter.)
You can buy the blades thru Linus Project.
I even crocheted around the pillow. My grandaughters in Indiana each received one.