please do skink, now im interested, you could revolutionize smoking if you were able to find a suitable one-way check valve that is small, easily integrated into bongs/pipes etc, and there might even be a way to rig one so that it doesnt get resinated and cause leaks, which would be my main concern.

the stem is a great idea but what if you COMBINE the stem, and the valve idea.

have a valve at the bottom of the stem, that way you still have all the benefits of the stem, plus you cant blow-back and soak your weed, that would be NICE.