Poking and Boning are simple variations on your riding style much like Fakie is to Normal riding. When riding down the hill or when you are in the air you change the way you are standing on your snowboard and thus Bone or Poke the trick you are doing.
Boning and Poking is the art of extending an edge of your snowboard past the point it would normally be at by straightening one of your legs. The act of straightening your leg naturally pushes that edge of the snowboard past the point it would normally be at. As you have undoubtedly guessed, you can do Nose or Tail Bones and Pokes.
Pokes are done while you are riding normally. Begin by riding down a hill that is fairly even so as to avoid hitting a surprise bump and loosing your balance. You must be riding in a flexible way as you are going to change you center of balance. When you are ready begin by flexing your legs a little more than usual and thus lowering your body a little closer to the ground. While keeping your body in basically the same position straighten your forward leg. This will push the nose of your snowboard out in front of you. You must compensate for this by flexing your rear leg a little more.
Boning is much the same but it is done in the air. The process for Boning is the same as Poking but a little more exaggerated. When you leave the ground bend you rear leg slightly more than you would for a Nose Poke and extend your front leg. This will cause you to do a Nose Bone. To land the Nose Bone put equal weight on both legs while straightening them to a normal position and flex them a little as you would for any landing.
Bones and Pokes are a simple variation of your riding style that you can add to any trick. Nose Bones and Pokes are much easier to do than Tail Bones and Pokes but with a little practice you will be able to do either perfectly. Work as hard as you can to progress to Tail Bones and Pokes, as they look even better than Nose Bones and Pokes.