Opinions vary on whether electric clippers or a regular straightedge razor are best for this.
Personally, I think a straightedge razor gives MUCH smoother results. Also, I have found clippers have a nasty habit of nipping the sensitive skin down there. In my experience, a straightedge razor is also less likely to result in itching as the hair grows back.
Taking a straightedge razor to your privates may sound scary, but if you do it in the shower and lather yourself up very well with soap, there is almost no risk of cutting yourself, in my experience.
Steve