What is the proper way to hold the arnis stick?

The answer is , "it depends". If you mean while carrying it while hunting there are several ways. If you don't expect any game to pop up or you are unloaded walking in or out of the woods then a sling over your shoulder is fine. If you are stalking expecting to see game any second then hold it with your trigger hand by the pistol grip with your finger out of the trigger guard, safety ON and your other hand under the forend near the balance point of the gun, muzzle up in front of you. Be careful if you are hunting with others, watch your muzzle and be aware of their location also look out for other hunters in the woods. Never point your gun until you are sure it's the game you want to shoot and there is nothing beyond the target you may hit by accident. Another way to carry it casually is to hang it in the crook of your elbow. bring your forearm horizontally across your midsection and let the gun hang in your elbow at about the pistol grip. Be careful not to get mud or snow or anything in the barrel, bad things will ahppen if you shoot it while it's plugged! It's not too hard to bring the gun up to shoot if game appears but it's not an ideal way if you are trying to flush game.

Now, holding a rifle to shoot while standing is fairly simple. Stand with your feet slightly apart and roughly 45 degrees from the target (if you drew a line across the tips of your toes.) Place your non trigger hand on the bottom of the forend ahead of the trigger guard at the point where the gun will balance, elbow under the gun. Some guns don't have a good balance point like this so you'll have to see what's comfortable for your gun. Raise the butt of the gun up onto the front of your shoulder just above the armpit, place your trigger hand around the grip, elbow out to the side almost horizontal, again don't put your finger on the trigger yet, and put rearward pressure to press the butt into your shoulder. Believe me, if you do this it will reduce the felt recoil of the gun. Now align your sights on your target, release the safety, place your finger on the trigger at about the first joint. Take a deep breath, slowly exhale, stop and squeeze the trigger. The gun should fire almost as a surprise, you don't want to snap the trigger, you'll pull off target. Practice this and you'll soon be shooting more accutately. If you are in the field always try to find a rest on a tree, your back pack or with your elbows on your knees if you are sitting. Even drop to one knee if you are in the open, anything to help steady the gun.

Good Shooting!