One of the most frequently asked questions at EARPLUGSTATION is how to to fit earplugs properly. Foam earplugs can be particularly difficult to use properly and many people complain that their foam earplugs don't work or fall out. The problem is most probably that you have not been inserting your foam earplugs correctly. Watch the video below and check that you're on the right track! Chances are you've been using them incorrectly for years....
http://www.youtube.com/watch?v=3S6dthcSVIM