Lip gaffing is one of those things that works out better in theory than in practice. It works IF you can get the fish to open its mouth, or IF you can turn the head right at you so you can come up from under the jaw. And in the latter case, the distortion (refraction?) of the water can cause you to be off by just enough to come up under the gill plate. Best way to do it is grab the leader, bring the head out of the water and come up under the jaw, but that sometimes requires one more hand than what God gave us.
If you want a laugh sometime, go out to Montauk and watch someone try to lip gaff a big bass with one of those short-handled belt gaffs under the light, while 6 footers are coming onto the rocks. I imagine they do make it easier to lift a fish out of the crevices between those boulders after the waves sweep them in
