Place pork shoulder/butt in crockpot. You can remove the fat if you'd like, but I like to keep it on to add extra flavor and then remove after cooking. It's also easier this way. (See instructions above for searing meat before using the slow cooker.)
Pour Coca Cola and orange juice over pork. Sprinkle with garlic powder, salt and pepper. Add onion.
Cook on low for 8 hours or high for 4 hours.
When finished cooking, remove from crockpot and shred with 2 forks, removing bones and large pieces of fat. Do not return meat to crockpot.
Heat a skillet (cast iron preferred) over medium heat and add 2 Tbsp canola oil. Working in batches, fry the meat in the skillet until edges begin to get slightly crisp. You just want a bit of crisp edges to intensify the flavors, don't over cook.