Place the sliced onions and garlic at the bottom of your slow cooker.
Set the pork shoulder on top and rub with paprika, chili powder, salt, and pepper.
Pour the Dr Pepper around the meat, then drizzle the barbecue sauce over the top.
Cover with lid and cook on LOW for 8 to 10 hours or HIGH for 4 to 5 hours.
Once the pork is tender, shred with two forks right in the crock pot.
Mix the shredded pork with the juices and sauce until well coated.
Serve on buns with extra barbecue sauce and coleslaw if you like a little crunch.