I tried a small one many years ago and I don't remember it being too difficult. We stuffed it from the back and did very tiny, close stippling around each shape to puff them out.
If you want to see what I made, go to my Flickr account-8th one down on the right hand side.
I haven't done any since, but know I could probably do another small one.

Hugs, how are you feeling today? Other than all your excitement on waiting for your mail to come this week? )