Normally, you would yell at someone to ‘put a sock in it’ when you want them to shut, but that probably wouldn’t appear too visually comprehensible when drawn poking out of the ceiling. It wouldn’t be very watertight either. hence the change of the sock to a cork, still a phase that’s used quite often, but not one I’d automatically reach for.

I drew an old fashioned incandescent bulb in frame three rather than a low energy one for much the same reason.