In my experience, it means dip your fingers about two knuckles deep into a glass of water, then hold them over the glass of single malt you're drinking for long enough to let them drip a few times. It really doesn't take very much water, IMO, to let the single malt open up.A couple of you have mentioned "a few drops of water." What does that mean? An ounce? Fifty/ fifty? How about soda? I know it's no ice.
I don't prefer soda water with a single malt; if you're drinking a blended scotch and soda, my understanding is it's something like a 4/1 soda/scotch ratio, depending on bartender.