There is another thread on this topic. It's called "Shaving", and at this instant it's the bottom thread on the first page of My BDSM Life section. If you wait too long it'll be the top thread on page two.

I shave monthly. Just use soap and water and a Gillette Trac II razor. If you find you've missed any afterwards, go to the tweezers. I think you're more likely to cut your scrotum than you are your penis (at least that's been my experience).