I made a basic 9cm by 10cm egg cosy dome from felt, then cut out tiny circles from felt and also the red markings and blue 'metal' tabs. I glued the pieces into position then sewed a small x in the centres to keep them there permanently, then stitched the front to the back. The back is plain felt but could be also be decorated, also on the wrong side of the front you could iron on some bondaweb and a piece of linen to hide the stitches.