I have never really been able to hold back my sneezes before. Yesterday I figured out how to! I can only do it for about 10 secs though, but it might be enough to help me get away from certain situations.
Its not totally unnoticeable however. I discovered that if I start to hitch before starting to sneeze if I close my mouth it stops for a sec, then the hitching starts again. I can do it again a few times before the sneeze overwhelms it. I can usually do it for 3 times, and I was able to do it 4 times once.