I nick myself occasionally when shaving my facial hair. I've been shaving my balls since ~17 years old and I have never cut myself. I'm not particularly careful either. I mean the first few times you do it you are but after awhile you just stop being a wuss about it. I don't use shaving cream/gel either. I did initially but found it just takes more time and just isn't necessary. A few minutes in hot water is enough.

Just think about it like you're shaving bubble gum. You gotta stretch it out. Unless you're using a straight razor I wouldn't worry about mangling your junk.