Pour the Thai chili sauce, guava juice, hoisin sauce, sesame oil and soy sauce in a large slow cooker. Stir to combine.
In a large bowl, mix the pork sausage, eggs, garlic, ginger, grated serrano pepper, and panko, until evenly combined. Using a 1 1/2- to 2-tablespoon scoop, measure out equal portions of sausage mixture and roll into tight balls.
Place the meatballs in the slow cooker and cover. Cook on low for 4 hours, or on high for 2 hours. Serve warm.