I use a dull-ish razor on my balls and shaft. Usually it's one that I've used on my face for a few weeks, then swap out. I also use a trimmer for the section between my navel and shaft. Usually 10mm. I had a comment that it was prickly when I bring it down shorter. Inner thighs I go down to a zero, but usually get shaving bumps after which is annoying.

Lately I've tried Nair hair removal cream instead of my trimmer, and that's been an interesting experience. I usually prefer a bit of hair below my navel because otherwise I look like I'm 9 again, but it's been good for my inner thighs.