It may be a myth or not, but it SEEMS to work for me . . .

If you happen to shake up a glass bottle of beer or soda
and are afraid it'll come shooting out if you open it,
rap on it with something made out of a hard metal
(tools, keys, etc.) for a little while. Then, that won't
happen when you open it.

Now, this COULD work just because the extra time
you take rapping on the bottle gives the gas time to
become stable in the liquid again.

However, I have noticed that the tone of the sound
made by the rapping changes as you do so. It starts
out dull, then becomes more ringing as you keep
doing it. When it rings like a bell, you can open
the bottle. Simultaneously, with the change on tone,
the foam on the inside of the bottle collapses.

So, MAYBE, the sound is somehow modifying the
liquid-gas characteristics.