No, you "use" it on them like a Protein or HP UP.
From the game you press the X button to bring up the menu. Then you press the up or down buttons until you have selected the BAG option. Then you press the A button. Now, you press the left or right buttons until you're in the bag pocket that says BERRIES or just touch the little berry icon on the touch screen. Now, you press the up or down buttons or scroll using the Pokeball on the touch screen until you have reached the berry that fits your needs. Now you press the A button or the center of the Pokeball. Now, you press the up or down buttons or scroll using the Pokeball on the touch screen until your cursor is on the USE option. Now press the A button or the center of the Pokeball. Now, use the up, down, left, and/or right buttons to choose the Pokemon you want to use it on. Now press A. Now, the Pokemon's EVs have just been reduced. Repeat until you are satisfied or when the EVs can't be reduced any longer.