Before you do your next smoke for pork or brisket wet rub with prepared mustard and oyster sauce. Make it about 60/40 mix with the mustard dominant. The oyster sauce I am using is "Panda" brand and has a panda bear on the bottle. "Dynasty" is another brand of oyster sauce that I have used in the past and it is certainly almost as good but prefer the panda.
Be liberal with the rub and let it sit at least over night in JUST the wet rub. Put your favorite dry rub on the meat and sit another night if you can or at least 7-8 hours. Let me know what you think.