Counter PSA: Did you know that your body is sneezing for a reason and taking all the air out of it may be counter productive and actually lead to more sneezing?
Your body is often sneezing because it has been hijacked by a virus that triggers the sneeze in order to spread infection.
Sneezes were evolved before the invention of the handkerchief and tissue.
Unless I inhaled pepper that never happens. I've watched others learn this technique too even large men. It can take years of practice though, just like learning any good habit/manner.
I think the question is if you've considered that not sneezing completely may encourage a situation where you sneeze more often. If the sneezing is actually a helpful thing, it might be a problem to inhibit it.
As someone with severe seasonal allergies, it certainly does happen to others. Its not about manners or habits for everyone.