Definition: Priming a rubber is talked about in reference to speed gluing the rubber.
New rubbers that are to be speed glued are primed by applying a layer or two of normal glue to the rubber, and letting it soak in and dry to build up a glue base. Since speed glues actually have a low amount of glue component, priming the rubber allows the player to use speed glue on the rubber without the rubber falling off the blade halfway through a match. Some players also feel that priming a rubber improves the performance of the speed glue.
Priming the rubber could also be done by putting about 3 or 4 layers of speed glue on the bat, letting the glue sink into the sponge and dry between layers, but most players prefer to use normal glue for a rubber prime.
