the science of sneezing

Here's something I've never understood: how do people stifle their sneezes? Some people are able to sneeze really quietly, and I've no idea how.

Also, have you ever been told that if you need to sneeze, you should quickly look at a bright light? Is it just me or does that never, ever work? I can't think of one occasion where it has for me. Could it just be propaganda spread by Specsavers trying to make us all go blind staring at the sun or something?