Dr. Jim: Would you believe great minds ... I've done what you illustrate, using rubber tips that are used on pipe stems after a smoker has chewed holes in the ends. But that's not what I had in mind with my squeezable cartridge post. I smoke the e-cigar mostly and want the section where the cartridge and fluid is contained to be flexible, squeezable. That way, when the atomizer needs a squirt of liquid, I could pinch the area outside the cartridge and inject some liquid forward onto the atomizer. Like squeezing a tube of toothpaste.
That requires more modification than any of us can do, I fear. When companies get around to new designs, I'm pretty sure they'll think of ways to inject or squirt liquid or gel onto the atomizer surface. For my e-cigar, I'd need the main tube itself -- housing the battery, atomizer and cartridge -- to be semi-rigid but squeezable. Surely, a plastic tube would be lighter, as well. This metal one is pretty heavy to hold by the teeth.
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)....it can give you controllable amount of liquid by squeezing it ...not easy but feasible...still looking for manufactured parts.... 
