There are two ways that you can find: either put bendable wire into the jaws that can be manipulated into an open/closed position, or develop the "Grusderk" method of pulleys that open/close the mandibles just by moving your jaw. That one is more realistic but also a LOT harder to perfect.
It would be the **** if someone could actually come up with this for members here. How freaking cool would it be if you could walk around and open the jaw at your whim? Not only that, but it would be nice to see another mask other than the highly popular DBP1 that is so predominant here. I love the mask but its sad that sooooo many people have it now.