I'm inclined to say yes. Only people I know that color their hair are women. I'd probably make fun of you for it. But ... just because you get made fun of doesn't mean you can't do it. There are worse fates. Decide for yourself -- then do what you want.
That black coffee idea sounds preposterous, though. If you're gonna do it, just buy hair dye and do it right.
Dying your hair isn't unmanly amigo, but fretting over your friend's opinion of your grooming is something you should reflect on. If you want dark brown hair, go for it. Might I suggest trying the coffee on a weekend or a day when you don't have to work.
If you're thinking about coloring your hair, I can't think of a manlier way than using black coffee.
Never heard the coffee thing (the things you learn here on AOM), but based on this, it sounds kinda complicated (plus I can't imagine shooting cold coffee on my head via a spray bottle; but that's just me). http://answers.yahoo.com/question/index?qid=20080615120117AAOLdVY
The above link is pretty funny, though (use tea for chestnut highlights; no instant coffee; be sure the coffee is not hot -- what is this, McDonald's? -- etc.). One person even posted a video tutorial using Dunkin Donuts coffee (would Eight O'Clock Coffee wear off by noon? Would Starbucks coffee give a more expensive-looking color? I have so many QUESTIONS): http://www.youtube.com/watch?v=NITO7ZEbzF0
What I haven't seen anywhere is how long this dye job would last. You might want to find that out first in case you don't like the result.
Anyway, I wouldn't dye my hair personally, because once you start it's hard to stop. (Also, my wife likes the gray coming in; I'm just happy I HAVE hair.) To me, it reminds me too much of this: http://www.youtube.com/watch?v=eSew8xM3L_E
Good luck. If you decide to do it, post before and after photos so we can all learn from your (hopeful) success.
I like my grey.
I don't think it has anything to do with masculinity. My natural hair color is pretty ashy and I prefer it to be darker. My wife (a hairdresser) colors my hair when I request it and I feel no less masculine wearing it the way I prefer. I think striving to be an "integrated man" includes leaving these insecurities about perceived masculinity behind. Also, there is evidence ancient male Egyptians colored their hair dark, contradicting the gender norm you describe.
Dudes in ancient Rome were putting bird shit in their hair to make them appear older and by association more wise. I don't think it's unmanly, but I spend a better part of my day trying to keep bird poop away from me. Also hair dye. Except when I was a teenager in a punk band I had blue hair. I agree with what you say about the integrated man as long as it doesn't include wearing pink socks.
I think it depends on why you're doing it. When my hair was thinning at top, I used colour (my own natural medium brown) to thicken it. I'm not sure what I think about completely changing your colour, though, unless perhaps you've gone salt-and-pepper and it's just not working. In that case, going one or the other should be fine.
i'm 25 almost never colored my hair at all and going grey i don't see a reason to color my hair