Set the IP to Saute and heat the oil.
If the pork is too big to fit in one piece, pull apart or cut the meat up into 2-3 large pieces. Sear the meat on both sides until dark brown and caramelized, about 8 minutes per side. Hit Keep Warm/Cancel.
Combine the apple cider and apple cider vinegar and pour around the pork (don't pour it right on top of the pork or it'll wash away all the spices you just rubbed in).
Use the Manual function to set your IP to 60-75 minutes, depending on the size of your pork. When done, hit Keep Warm/Cancel and let the pressure release naturally (about 20 minutes). Try to shred one small part of the pork with two forks. If it's easy to shred, it's done. If it's still tough, add another 5-15 minutes. When it's done, core the apple and cut it into 8 slices: cut it in half, cut those halves in half, and now cut those pieces in half. You should end up with 8. (Don't do this before the pork is ready or the apple will brown.)
Remove the meat to a bowl. Hit the Sauté button to bring the sauce to a simmer. Add the apple slices and cook, stirring and flipping occasionally, until just slightly softened, about 5 minutes. Hit the Keep Warm/Cancel button.
While the apple cooks, shred the meat with two forks. Toss the meat in the sauce to make sure it's all coated and serve with the apples.