I have always used side cutters to cut the skin between the gills under the bass' head. If you cut it all the way through, the fish will bleed out and die very quickly. I always just cut them and throw them back into the lake. Something will eat them. I have had large bass come to the surface and bust them before they die. Now that will get your heart rate up. I would not do this if I caught a hundred bass a day, but a few every week or so is not a problem.
