When I originally submitted the werewolf doll, someone had asked how I attached the clay head. I'm terrible at explaining things when I can't just show someone IRL - I hope this helps!
For reference, here is a progress shot of the doll's head prior to baking the clay: [link]
You certainly don't have to make the creature's head with coloured clay, you can always paint all of it after baking.
Leave a stump beyond the face or head, which will later be embedded in fabric. Or a bit of an edge, whatever. Poke a bunch of holes in this before baking - if you prefer, stick a whole bunch of sewing needles in it, and leave them in while it bakes. They'll be easy to pull out after baking the Sculpey.
I don't know how this would work with any other clay, as some shrink while curing...
I'd also recommend forming the 'core' of the head out of tinfoil or paper or something, so it's not TOO heavy.
Now, where I attach the clay face to the fabric body, I leave a sort of tube of fabric - I cut it much longer than I know I'm going to need. Settle the head about where you like it, and whip-stitch the fabric to the holes you poked in the base! Make it nice and tight.
Faux fur is recommended, as the fur pile - even short ones - is more forgiving. The fabric may pucker a little, or show the stitches, but it'll be hidden in fur pile. C:
Then I use a super sharp razor, and just sort of eyeball and cut the fabric to where I want it to 'end' at the clay face. Then glue those flaps down! Go slow and careful. I take a needle and gently poke the very edges of the fabric under, so cut edges don't show at all...
You may also have wanted to stipple the clay head stump everywhere it will be covered by fabric; just poke or scratch at it with a needle. This will give some texture for glue to stick to.
For glue, you can use whatever you like. I recommend E6000, Gorilla Super Glue, or any polyurethane glue, as I know they all stick very well to polymer clay.
Tacky glue will also work, but it seems to take FOREVER to dry, and it's easy to bump it accidentally and shift everything out of place. You could also use Krazy glue, but I find it sets TOO fast before you can get everything just right.
If this helps anyone, please share pictures! C: