Combine paprika and cumin in a small bowl. Season with salt and pepper. Rub pork all over with the spice mixture.
Place pork into a slow cooker. Combine stock, barbecue sauce and mustard in a bowl. Whisk until well combined.
Pour mixture evenly over pork. Cover and cook for 6 hours on high or until pork is very tender when tested with a fork.
Turn off heat and stand for 20 minutes.
Transfer pork to a baking dish. Shred pork with 2 forks.
Stir 2 cups cooking juices through the pork.
Use shredded pork immediately or chill in an airtight container in the fridge for up to 4 days or freeze for up to 3 months.
