No, no ,no - please don't resort to forcing your pony to accept something that he's clearly not happy with. Forcing his mouth closed with a flash noseband is just plain wrong, IMHO, and a quick fix without any regard for the dignity of the animal. A happy pony will carry the bit himself because it is a communication tool.
My Shetland is very mouthy - loves to play with buckets, ropes etc but he's not that happy with a bit. He's got a Dr Cook's bitless bridle, which he's quite happy in.