In my experience, it does not matter. Although, I always added water to NaOH pellets to make a NaOH solution. However, whenever working with chemicals always wear protective gear.
In my experience, it does not matter. Acids are another matter, however. You must add acid to water, not water to an acid. It is a very exothermic reaction, and if you add water to the acid, the water-acid may be thrown out of the container, causing a chemical spill and potentially causing bodily harm. I used to give my students a way to remember the right way to combine acids and water. The letter A comes at the beginning of the alphabet, and the letter W comes at the end of the alphabet. So Acid goes into Water.