leg on the tube, and feel my manhole. Then I use the trimmer to trim. You have to be careful with the trimmer, and work your way. After I feel that I have made adequate progress, and there is only a small amount of hair left, I use the shaver to shave the remaining hair off.

As for my balls and hair around my shaft, I also use the trimmer and shaver.

I'll say it again.  LASER HAIR REMOVAL.  Ask for the "Men's Brazilian".  Get the multiple treatment package.

I've had six treatments now, and I have almost no hair growing down there whatsoever.  And the hair that still grows is fine and sparse.  I have three follow up treatments as part of my package deal to get rid of even more.

chest. Then reach under with a disposable razor.

I have found a provider in the area who knows how and loves to do it.

It wasn't as painful as I thought it would be, and it looks great and lasts several weeks.

I wash back there with soap, leave soap on.  I have my own disposable razors in the shower, lift one foot & squat slightly & am able to shave the hairs out of the crack which would make contact when I do my business.  If you use your wife's razor, you are sure to be in the dog house!

To change the subject...  I learned to cut my own hair when in high school (sister taught me...  with proper barber's sissors).  In college I learned to shave neck & trim with a disposeable razor.  After shampoo, I still reach over & shave back of neck.  I use a bikini shaver to trim over ears.  (Wifee wanted to know why I had bought them!!)  I don't do full haircuts anymore but I can extend a cut & still look good (at least the hair cut) this way.
HV

Ask a provider! lol

Why not?  Some offer shaving, and/or trimming services.

Butthair

I shave my girlfriends butt hairs but never a guys...

as someone said above, best way is to squat in the shower with a razor..... i have hair trimmers that pinch/catch skin.... that fucking hurts! never had a problem with a plain razor though