Jorge Rubicce imitates wool texture in this cold porcelain video demonstration. He also shows how to create the effect of hair peeking out from under the wool cap. Notice that the head he is working with is fully cured and he uses white glue to attach the additional cold porcelain for the cap.
If you don't understand the language in this video, just mute the sound and follow along visually. Each step is clearly shown. Rubicce is a well-known cold porcelain artist in South America and this is an excerpt from the television show Bienvenidas. Fast forward to 13:03 to view the segment with Rubicce.