Open a can very quietly.

Sometimes when I go to class, I'm real thirsty, so I bring a coke with me. It gets kind of uneasy when it's dead quiet, then it's all broken up with a "PShkrtt".

Anybody know a way to open a can really quietly? I tried doing it real slow, letting the preasure inside leak out slowly, but I was wondering if there is a quicker way.