[brumblebear]

There are 3 basic ways to go about getting a dog to drop whatever it's holding in it's mouth under normal circumstances (as in it's not the best sausage in the world and already halfway down it's throat!) if it won't respond to a "drop" command:

• Since a dog usually holds items around the front of it's mouth, you should be able to slide a finger behind the object, between the dog's jaw, and push down on the back end of its tongue with your finger. This usually causes the dog to let go of whatever its holding.
  
• Cover the dog's eyes with your hand and then pull the object out of its mouth. This trick doesn't work on all dogs, but most dislike not being able to see and will twist their heads and simultaneously release their jaw when their eyes are covered.
  
• Place your hand over the dogs muzzle and squeeze your thumb and forefinger from each side between the back of its jaw - you'll basically be using the principle of leverage to pry the dog's mouth open.

There's another slightly unorthodox way to make a dog release an object, and that's pulling it straight upwards by the throat with its collar (the emphasis is on straight up - as in completely vertically). This constricts the dog's throat as strangling would and the dog's weight against its own throat is usually enough to make it let go. If the other 3 methods don't work and you're absolutely desperate because the dog is about to swallow something dangerous then try this.