But isnt it easier to just pull your thumb off? That way your hand can remain holding the bong without using extra fingers to take out the plug.

And when I am hitting a piece, I like to hold the carb down for abotu 10 seconds, then release, then hold it down for another couple, then release the final time. That would be hard with a little plug that had to placed in and out, especially since it would need to fit rather snugly...

Paul