I know that in the hot weather both of my dogs like to be wet down with cool water or rapped in a towel just to help ward off the heat...of course this doesn't always help with them both being mostly black.

If you really don't want to wet the dog down though becuase of the matting of the fur you can actually get things that do the trick without actually making the dog wet. They now have these cooling pads out that you soak in water drain out and put in the fridge for a while then you put them in a cover of sorts and it's sort of like a cold pillow for the dog. There's also a vest like that avaliable that you should be able to buy at dog shows or maybe specailty shops....of course there's always the cheap version of the cooling pad and that's getting cooling packs throwing them in the freezer then putting them in a pillow or dog bed. If you still want to wet the dog down but don't want to wet the whole dog try wetting the stomach as that's a major part that regulates body temp.