I think silent soul needs just a wee bit more help. What you need to do is stretch the skin of your sac taut. Two ways to do this. First is to maintain a boner while you do it (tough with a razor so close to your manhood), second is to use fingers to stretch the shin as you shave it. If you don't do this, you're gonna bleed! Definitely lube it well. I've done it in the shower, it just adds a little moisture to the whole process. Be careful!

__________________
Lots of people talk and few of them know, soul of a woman was created below

I can't get through to her 'cause it doesn't permit
But I'm gonna give her everything I've got to give.

I hear your sweet voice calling
out my name
As I stare from a six foot cell
And from beyond I heard the words
Deceptively Yours