The best way to get them used to clippers is by doing a desensitization process. Like some one else mentioned, start out first by just turning the clippers on in front of him, but a few feet away. Once he gets calmer, come closer. Continue to do this until you can touch him. While the clippers are going, rub his face with your hand and stroke his ears. I remember watching a training technique that said stroking their ears helps to calm them. Once he starts to drop his head (usually they do this when they are calm), put the clippers on his nose. Then try and clip the muzzle area. Try and work your way up his neck with them so he can get used to them being behind his head. Put them on top of his head between his ears. Now you can clip the bridle path and the ear tufts. This might take a really long time, or you might only be able to get to his muzzle or neck before he starts to freak. Just keep trying and be patient. If necessary, you can stretch this out over a few days, or even weeks if he's that skittish. Good luck!!