Step 6: Creating the jaw
Once the jaw is attached, you may notice the mouth fabric feeling a bit floaty. You can weigh it down to give a it a better sense of being a "mouth" by pinning a small weight to the inside of it to create a sort of "throat". A knot of left-over fabric works well for this.
One tip, when holding up the jaw in the "closed" state, your eyes should fit just between the tip of your jaw and the upper edge of the mouth. This way you can still see without your Yip Yip opening his mouth.