Tap tap is the old practice of tapping the turret after an adjustment to settle in the erector spring . Turn the turret with a coin then take the coin and tap the top of the turret a few times. Also on some scopes you can feel more spring tension in one direction than the other. Always finish your adjustment a few clicks in the stiff direction. So if adjusting to the soft side, go a few clicks past and then come back. Accomplishes same thing.
Of course this is not necessary with a quality scope. A lot still tap tap with Leupolds, maybe out of habit, maybe not.
