On Thursday I will be using a rub for the first time. Naturally, I have a question. Will the marinade help keep the rub in place or do I need something like mustard to "cement" it down?
Personal preference. Using something like mustard adds another layer of flavor. But it's not needed. The dampness of the meat of hold the rub. I've only ever used rub on bare meat.
I would start without adding anything else. Next time, if you want to add more/different flavor, then try using a mustard, honey, etc.
A big help to getting a good answer would be as always. Give all the info needed . Meat Poultry Fish all get treated differently.
Olive Oil Salt and Pepper, I like on Beef