This will create a paste that the rub will stick to. Here is a recipe for the rub I use on pork shoulders. After you apply a layer of mustard to the pork shoulder, completely coat the shoulder with a good BBQ rub.
yes, its a thing, a noun is a person place or thing. Shelter is a usually used as a noun: We built a shelter to sleep in during the snowstorm. It is also sometimes a verb: We were told to shelter in place during the fire. The trees sheltered us from the hail.
To take refuge is to find a safe place. You might take refuge under a bridge in a hail storm, or in a basement during a tornado. Refuge comes from a French word meaning to flee, and, in most cases, a refuge is a place to flee to in order to get away from people or places that are unsafe.