Many people are saying erect, but I'm going to have to chime in with semi-erect. Of course now that I read that it sounds like a humble brag, and that's certainly not the case.
Anyways, as others have said if you aren't going to shave often, trim. Stubble is a bitch to a vagina or a mouth.
But what if, like me, you enjoy not coming up from oral looking like a brillo pad? What's good for the gander is good for the goose, right? Fairness and equality and thoughtfulness! The Golden Rule! Thou shalt not have a forest and expect oral if thou expects a field to give oral!
I use my DE, omega brush, and proraso green (well co bigelow whatever). The brush, I find, seems to do a good job exfoliating and getting the hairs separate and standing up. I should note we are doing this on a clean groin.
Now I am nearsighted, but sometimes I enjoy the challenge of doing it sans glasses, because water droplets can be almost as distorting. This leads me to the inevitable. Yeah you may nick skin. Cry about it. Typically I don't, but I'm not going to say it hasn't happened, to the shaft or the sack. Just throw some alum or styptic on it when you're all done and remember what it feels like to be alive.
Now the other area that you are going to want to take care around is the big vein on the topside of your shaft. You don't want nicks there. I don't know what it would be like, but I don't consider myself man enough to try, and I come at that motherfucker with Feather blades.
Should you decide to expand to getting your taint/ballsack/dick crease (you know, that half cm around the dick that likes to do Bush impressions), you will have to worry about slipperiness.
Balls covered in cream don't make the most stable surface. Some methods include "Batwinging" where you pull one pinch out to a point, and then shave the opposite side, or "Flying squirrel" which is a sort of double batwing.
I personally like the "Turtlehead" which is great for the underside of your balls. Basically pull the loose skin up and over your shaft so that the little crowned german is poking out like a turtle. This is also a good way to get to your taint.
But really the shaft and the taint, even the Amazonian Rim are all pretty easy. Its the balls that are hard.
I've given up and started using Magic Shave Powder or Veet for my balls.
Finally you have to remember about the rest. Should the main forest be well tended new growth? Old, virgin rainforest? What about your thighs?
Those questions, my friend, are for you to find out in your own time. But I will leave you with one last piece of sage wisdom.
The asshole. Don't shave it, trim at most. Prickly asshole is about the most annoying amount of non lifethreatening pain you will ever care not to experience.