If you're making lap cheong, start by mixing the ground pork with soy sauce, Chinese rice wine, sugar, oyster sauce, Chinese five-spice powder, and white pepper in a large bowl. Ensure that all the ingredients are well combined, and the seasoning is evenly distributed throughout the pork.
If you're making lap yuk, marinate the thinly sliced pork belly with soy sauce, Chinese rice wine, sugar, oyster sauce, dark soy sauce, Chinese five-spice powder, and white pepper. Allow the pork belly to marinate for at least 30 minutes to absorb the flavors.
For lap cheong, you'll need to stuff the seasoned ground pork into sausage casings. Chinese sausage casings are available in Asian grocery stores. Soak the casings in water for about 30 minutes to soften them before use.
Fit a sausage stuffer or a piping bag with a large nozzle and fill it with the seasoned ground pork. Carefully slide the casing onto the nozzle and gently push the pork mixture into the casing. Leave some space at the ends to tie off the sausages.
Once you've stuffed the casings, tie off the ends with kitchen twine or a twist tie. If you're using natural casings, be gentle while tying them to avoid any breakage.
After tying off the sausages, you can shape them according to your preference. Lap cheong is usually formed into a horseshoe shape, while lap yuk can be left as straight links or tied into loops.