It's when the atty "nub" sticks out (like the SuperCig or E011) and you dunk it like a donut into liquid. I think most people still drip onto the tip as it seems like a big waste of liquid to prepare a dipping container.
Not if you use a contact lens case! Because it's made to hold a tiny amount of fluid, and the bottom is rounded (mine are, anyway), so there's pretty much zero waste of liquid because the very last drop still rolls right into the middle where the wick can suck it right up. You probably waste more by dripping the first time you accidentally flood the atty and have to blow it out, or the first time you miss the wick, or drip too fast for the coil to wick and have liquid bouncing off the surface onto the table.
Also, when dipping you don't run the risk of accidentally dripping liquid through the atty hole into the battery, which can be bad. Remember, the atty is designed to wick liquid from the mesh exactly to the coil, so by dipping all you're doing functionally is, in essence, screwing on a perfectly topped-off cart every ten drags or so.
Plus, you can store two different flavors in the right and left lens compartments.
If you know anyone who wears contacts, they probably have a dozen unused ones they'd love to unload on you, because they often come free in packs of lens fluid.
BTW, if you look at the blu atomizer, you'll see why it's practically made for dipping:
Look at how far those wicks protrude! 8-o