The thing about vaping is that it's different from smoking. It works better if you embrace that instead of trying to avoid it or deny it. An ecig is best used in a different way from a cigarette as it works much better that way. The only real similarity between ecigs and tobacco cigarettes is they both go in your mouth. If you consider that ecigs can have any shape or functionality and produce a low-temperature water-based vapor, and are not rolled tubes of burning plant material producing smoke, it may be easier to comprehend that there could be some differences in use.
Inhalation technique when using en e-cigarette
It's worth describing this otherwise people may think an ecig is used in the same way as a cigarette - it isn't.
With the ecig mouthpiece placed in the mouth, seal the lips, and, creating a vacuum in the mouth by sucking (with the mouth only and not the lungs), draw vapor slowly and gently into the mouth. Draw a short time for efficient models such as APVs; a medium time for mid-size models; and a long time for minis. The draw-in period can therefore vary from 3 seconds to 8 seconds according to the efficiency of the device, the nicotine strength, and the required effect. Note this is not an 'inhalation' time since only the mouth is used; it's more like a 'suck time'. The vapor is still in the mouth at this time. Draw very gently on the ecig because a hard, sharp draw doesn't work, and may pull liquid into the mouth.
Keep the vapor in the mouth for a second or two, then inhale it if wished. You don't have to inhale vapor, nicotine is absorbed in the mouth and nose as well as the lungs.
If you inhale, then exhale slowly through the nose (if desired), as nicotine is absorbed in the nasal cavity.
You can see that a two-stage inhale is used, in contrast to the normal single-stage cigarette inhale.
If maximum nicotine benefit is required, do as above. If not, shorter draw-ins can be used; direct exhale through the mouth not the nose; or don't even bother inhaling, just keep the vapor in the mouth/nose area.
There are numerous variations on the above procedures. The main thing to remember is that an ecig is not used like a cigarette, so the inhalation method should be completely different if you require full benefit from the device. If you don't, it doesn't matter. The key difference is that while a tobacco cigarette may often be used by inhaling directly into the lungs with a single-stage inhale, an e-cigarette is very rarely used in this way, a two-stage inhale is used.
There are a number of reasons for this, including the need for a slow and gentle inhale to make the heater coil work properly; the need to heat the coil for a time before it starts to work efficiently (and the lower the voltage the more this is needed); the possibility of a hard draw pulling liquid into the mouth; the liquid base of the vapor meaning that absorption is just as efficient in the mouth and nose as the lungs; the size of the vapor molecules being ten times that of those in cigarette smoke (10 microns vs 1 micron) meaning that lung absorption is relatively poor compared to tobacco smoke; and so on.
To get maximum benefit / nicotine delivery from a tobacco cigarette, you just buy a box and light one up. No skill required - and above all no advice is needed.
To get any benefit at all especially any nicotine, and to avoid other issues, en e-cigarette needs advice and technique. It can't be used in the same way as a cigarette. It's amusing to see the results of clinical studies where the participants were told to, "Use the ecig exactly like a tobacco cigarette". Such methods are proven not to work.
There is some blame attached to some vendors here since they might even advise customers to do this. The reason could be their own ignorance, or a desire not to put buyers off by telling them the procedure is different - in other words a marketing ploy. It's very different indeed, and telling a new buyer to 'use it like a cigarette' has issues.
It is also worrying to see such things being done as it means people might be trying to inhale with the lungs or make similar mistakes. Indeed, some clinical studies reported that there might be some sort of issue as a result of "the difficulty of inhalation and its effect on the lungs". It's hard to decide whether this incompetence is hilarious or worrying. It's as if clinical researchers seem to think there is some kind of similarity in use between ecigs and tobacco cigarettes, and that they can test the devices without advice from experts.
This is the 21st century, not the 18th. Perhaps someone who thinks it is possible for someone to automatically use an iPad correctly after only having ever seen or used an abacus shouldn't be in clinical research.