I believe “tap the can” refers to inserting a screw towards the bottom of the can, and removing it to let the product flow. Then replacing it to keep air from being introduced from the top down, as would be done by removing the lid.
This is correct for “tapping the can”. I use a self tapping metal roofing screw with a washer on it for a good seal. You can also tap the top of the can and blow Bloxygen in it to displace any moisture laden air you might have introduced if you need to take the top off. Once you tap the side near the bottom, just remove that screw to dispense a bit. I brush it on and it’s self leveling. The can is thin so go slow if using an electric drill to do the tapping.