Preventing Demons from leaving their vessels?

Question

In the television series, Supernatural, thorough out the various seasons of the series on various occasions we see that Sam and Dean capture various Demons, try to talk to them but are not able to succeed as the demon leaves their vessel through the mouth of the vessel and escape.

My Question is, will it be possible to prevent the demon from escaping if he was gagged?

Answer 1

Although the Winchesters are never shown to use your novel idea, there are other ways to prevent a demon from escaping the body.

From Supernatural Wiki

A binding link is a symbol which keeps a demon trapped inside its Meatsuit i.e. the human it is possessing. The demon can neither escape voluntarily or be exorcised. A binding link may be related to the "binding magic" used on Curse Boxes to keep the evil inside.

Answer 2

I don't believe that gagging a possesed person would prevent a demon from being exorcised. The demon is essentially a tortured spirit, it's essense would probably leak through whatever gag was in the mouth, or possibly even violently remove the gag for the demon to leave.

There are a couple of ways to prevent a demon from leaving. The first being the binding link Keybrd mentions. It also seems that demons can't leave the possesed body as long as it's in a demon trap. Also, saying the exorcism prayer in reverse shows to shove a leaving demon back into the possessed body that it's trying to leave.