Has anyone ever used like a sweet chilli sauce, instead of mustard, to help the rub stick to the meat? Thinking of trying with like an Asian style rub for pork butt.
You don't need anything to make the rub stick. The meat is damp enough.
Now if you are looking to add flavor go ahead and try anything you want. If you've been using mustard you've probably noticed you don't get any mustard flavor.