That's EXTRA simple, quick and easy. It can be a little obvious, by I think that a white label with your name on it sounds a little too childish.
First. That should be the bottom of your pen.
Remove the black plug. Put some beads inside the pen. Shake WELL. Maybe you'll need to do that twice, it depeds on how many small beads you want to put in it.
It's done! Now you can recognize your pen among thousands (ehm...btw I don't think your school mates are 1000 xD) of other pens! :)