heh..."The Internet is for Porn" - Avenue Q
Anyway, I think I know what the OP is talking about. When I'm in class and open my MB it's fairly loud and people look at you, so maybe he is wanting to supress the sound so it doesn't distrub anyone around him if he's in a place where he needs to be quiet, ie class, library, work, etc...or it could be because he needs to please himself late at night 😉