Use your wife's razor. If she has one that has the soap surrounding the entire blade head, those work perfect. I too had never considered the thought of using a razor directly on the boys until it was time for the big V, but this was painless and worked perfectly. Separately, don't get a local anesthetic. Ask for the valium and fentanyl drip before you go in, I highly recommend it. I assure you that nothing you see, hear or feel will bother you in the least.
You do not need a perfect baby's butt shave. Just go slow, use a new blade and clear an area the doctor can get to. I disagree with Oden. Get the local and bring a mirror the help you see what they are doing down there. Oh, and do not mind the smell of burning flesh.
Take in some colored markers and draw stuff on the paper covering the operating table. Like, arrows pointing like a runway. Maybe some "Do not use rear entrance" signs.
For the love of God, can we please, please change the topic from snipping off our balls. You sick fucks. I'm not squeamish, but some things are just unthinkable.
If you want to castrate a hog you can simply strap rubber bands tightly around the base of his balls and they'll just magically fall off eventually.
A quick snip is better than 18 years of hell. @Frebis - Getting cut is a 15-20 min out patient procedure. Getting her tubes tied is much more invasive.