Here's what I found out about the glitch (I also posted about this stuff on the gamefaqs forum): When you are close enough from the place where money bags was last a coin, it will continue to jump around. Once you move away, it will eventually make its way back to approximately the same place and then turn back into a coin. You want to get close to it just as it turns into a coin, so that it continues on and turns into a coin. If you enter the area when it was last a coin and it's at the end of a jumping sequence, you can make it "bounce", and this will occasionally produce a coin (like in the second video). You can also make it jump higher than normal by entering the area as it starts a jumping sequence.

Normally if you wake one up and then run away from it, it will take one jump, and then another jump back to it's start and turn into a coin. So, what I would try to do is wake it up, run away from it, and then run back, trying to get close enough just as it finishes it's jump.