Just like to answer the question about nang/CO2 bulbs. Nang bulbs have a silver seal, while CO2 bulbs have a gold seal. Don't get them confused. By seal I mean the bit that is pierced.
Often thought about a pocket sized machine. I figure the best system would be one to exhaust straight to atmosphere, ie lungs. However to do this you will need to provide a serious pressure drop to go from the liquid to 1 atm. Also you need to prevent cold liquid entering your mouth. I figured these problems can be solved with a expansion chamber, or better yet a very fine mesh/ foam such that the liquid foam will soak up the liquid, then release it at a slower rate.
To reasearch this further look into the design of accetelyne, as in a oxy torch, pottles. They solve excess pressure problems but dissolving the high pressure gas into acetone.
Warning** This level of design is serious hard core engineering. You can't just take a trial and error approach otherwise you risk serious injury. Only to be approached by engineers.**