I already had a pillow form measuring 18 inches. So, I cut out my shirt...
with a 1/2" seam allowance on each side. Next, I sewed my seam, then zig-zagged for durability.
I cut out 7 circles in varying diameters - averaging 3.5 inches across. (Idea from here.)
Next, I pinched the felt together and stitched the bottom of my "scrunch".
I repeated for each circle, then placed all my scrunched circles together and stitched those together to form my flower.
Lastly, I safety-pinned the flower to my pillow (easily removed for washing).
The best part is actually the back of the pillow, which could be the front too. It's easily unbuttoned to remove the pillow case for washing!