Your goal with sneezing is to avoid the increasing loss of CO2. If you tend to get caught up is a series of sneezes where you may sneeze from 6 to 60 times in a row, then you know how long it can take to recover.
Each time you sneeze you effectively take a big deep breath, and then blow it out. Each time you do this you lose more CO2, which in turn makes your nose more sensitive, and then another trigger another sneeze is produced.
The more you sneeze, the more likely it is that you will sneeze again! The best approach is to avoid the first sneeze, or failing that the second sneeze. If you hardly ever sneeze, or sneeze only when something like a fly blows up your nose, then this approach is not relevant. However, if the tiniest little smell or atom of pollen or dust affects you, then you can benefit from this.
The sneeze is a useful tool for expelling foreign substances from your breathing system. However, when you have caused your sneeze reflex to become too sensitive [by losing too much CO2], then you will sneeze when it is not needed to remove a foreign substance from your breathing system. The sneeze trigger becomes too sensitive!
The main rule is that you should not try to smother or contain a full blown sneeze. If the sneeze gets to the point where you cannot stop it, let it out, and try to prevent the next one. If you try to contain a sneeze you have the potential to damage your hearing.
Before each sneeze there is always a warning that it is coming. This is the tickle or itch sensation in your nose. If you act quickly as soon as you feel the itch, you can prevent the sneeze.
Your actions consist of recognizing that your have been breathing too deeply, and you have lost too much CO2, so you must trap some more into quickly. The simplest way to do this is to stop breathing. You can hold your breath, just as you do in a Measurement Pause, or you can do what they used to do in the movies!
If you are a fan of cowboy movies you will be able to picture a scene where our hero and his partner are being pursued by a bunch of nasty bandits. At a very tense point where our heros are hiding close to the bad guys, the not-so-bright partner of our hero will begin to pre-sneeze. He will go ooh ooh hih, but before the loud achoo arrives our hero will place his forefinger under his partners nose, his breathing will reduce, and the sneeze will be avoided [saving them from detection by the bandits and certain death!] You do not need the banditos to stop your sneezes.
You need only the realization that greatly reducing the depth of your breathing will trap in more CO2, and will relieve the itch which start with the sneeze.
Everyone knows that the simple act of putting your finger under your nose can stop a sneeze it has surely been known at least as long as movies have been around. Now you know how and why it works, and you can make it work better for yourself. The same applies for most itches that occur in the triangle that can be drawn from the centre of your upper lip to your right temple to your left temple. This includes itchy eyes and itchy noses. If you find yourself touching your face to scratch your nose, or rub your eyes or check your breathing. See if you can make the itch go away just by breathing like a mouse. It is very likely that it will just disappear.
You can reduce the impact of things like pollens and dust mites [and droppings] if your reduce your breathing depth as soon as you sense these triggers. For example, if smelling smoke has made your nose itch and eyes scratchy in the past, then you can reduce this if your reduce your breathing depth. [Obviously better to avoid them if you can, but at least now you can cope when you have to.] Another example might be vacuuming or mowing lawns as this stirs up lots of dust and muck so you can reduce the effect if you suffocate a little while you are exposed. [Mouth closed of course!] So, to summarize about sneezing At the first sign of the warning itch in your nose that a sneeze may be building, stop your breathing, trap in some extra CO2, and try to make the itch reduce.
If you are too late to stop the first sneeze, try to stop the next one. Do this by doing a Measurement Pause straight after the first sneeze, and then breathing only just enough to stay alive. [Pretend there is a really bad smell!!]
Do not try to hold a sneeze in if you cannot stop or you may implode [just kidding]. Just work on stopping the next one. There is another benefit is stopping the sneeze cycle as soon as possible. Each sneeze causes the release of more histamines which make the whole area more sensitive. These chemicals stay in your face for quite a while before making even a slight breeze enough to make you itch. Once they break down, the whole area in the triangle described above becomes less.