I did that recently.
But all of a sudden, here it is December and there is that red wool. I should do something with it.
So first I washed it in the washer on hot setting and dried it in the dryer. But it wasn't quite felt-y enough afterwards, so I decided to boil it on the stove.
I glued another little piece of fabric over the top. Then I set the whole thing on another piece of red felted wool which was bigger all the way around than the top piece (basically a square).
I threaded my machine with some sparkly metallic Sulky thread (which my machine did not like at all), and I quilted through all the layers, first in a straight line star pattern, and then around the outside edges and finally around the inner circle. Then I trimmed it, following the shape of the upper piece as a guide.
Update: I made another one last night. This one went together faster.