Chop your onion and add it to the pressure cooker.
Season your pork with salt and pepper. Season it heavily. It will help to flavor the meat when its done.
Add pork shoulder to the pressure cooker.
Add barbecue sauce and water.
Close your pressure cooker and make sure it's sealed. Follow the directions on your cooker for doing so.
Set time to 60-75 minutes and start.
Once it's done, let the pressure cooker vent or feel free to vent it manually.
Open the lid and shred the meat with a fork.
Add more barbecue sauce to top and serve on a bun or alone with some delicious side dishes.