I do (try to) but for obvious reasons it is not very easy. Luckily, I'm not that hairy.
Before a lot of girls start saying that it doesn't matter to them: it does. I've heard numerous girls say that they will tolerate any kind of hair as long as it is not a hairy back. Words like 'gross' and 'turn off', frquently being used.
No, I have never seen the point in shaving my back, so I have never done it. But if suddenly I started to grow a lot of hair in my back, then it might be a different story, but I'd not go to lenghts to make me scar myself, I got enough of them already and besides getting scars from shaving yourself isn't exactly the kind of scars most men want.
But then - never met a guy with a particularly hairy back either. So yeah - he wouldn't need to.
Most girls don't like hairy backs. So that's probably why he does it - he's probably pretty conscious of it. Offer to wax it for him; or just suggest he gets it waxed if it bothers him, rather than shaving seen as it's not really working out that great for him, and must be a massive nuisance. I can't even begin to imagine where you'd start with shaving your own back lol.
I don't know any guy that does, of course I've never asked or seen many guys with their shirts off regularly. I'd personally rather the guy have a little back hair than have him going through the pain of the ingrown hairs. I have plenty of those down below, so I know how annoying they are.
I have never known a guy who literally shaves his back. In the summer time, if I'm lucky, my guy will let me use the tweezers and get the few stray hairs that show up on the back of his neck and shoulders. But definitely not enough to make shaving worth it.
If he's giving himself ingrown hairs and scarring himself, he is doing something very wrong? And how in the world does he shave his own back anyways?! Lol
I don't find back hair attractive, personally. Guys expect us to shave our legs, underarms and pubes, so what's good for the goose is good for the gander. Sounds like he might need some different techniques, though. I know a few guys who use hair removal lotion.