In a large bowl, combine beef, pork, bread crumbs, onion, milk, eggs, soy sauce, and hot sauce. Add salt and pepper, to taste. Using your hands, mix well to combine, then shape into 1 inch balls. This will yield a little less than 50.
Heat oil in large skillet over medium-high. Working in batches, brown each meatball on each side, about 5-7 minutes per batch.
Transfer meatballs to the slow cooker.
If you don't make the meatballs from scratch, you can start the recipe here with a 32 oz bag of fully cooked, frozen meatballs in the crock pot.
Blend all sauce ingredients in a fresh mixing bowl. Pour sauce over meatballs and stir to evenly coat. Cook on high 3-4 hours if using homemade meatballs, or 2-3 hours if using frozen.
Garnish with fresh parsley if desired, and set out plenty of toothpicks!