^^ This.
I used RDA's almost exclusively for two years because I couldn't find a "tank" that provided the flavor and air control my drippers had. My lone RTA (Kayfun Lite Plus) produced great flavor but the draw was too tight for my preferences and I had to "work" too hard to enjoy my vape.
I received a Uwell Crown 1 tank last summer, and I have to admit that it has pretty much earned most of my attention since. The flavor, vapor production, and air control is superior to any tank that I had used before. I'm sure that there must be other tanks on the market today that perform as well. I must admit that I prefer the Crown on a regulated mod only; I still prefer using a RDA with my mech.
Squonking is just dripping "upside down", as PBusardo says. Instead of carrying a separate bottle of e-liquid with you, the bottle is inside the mod. One less thing to grab when you leave out of the house. So you get the flavor of a dripper, but the convenience of a tank, all in one device.
If you like a Kayfun but need a direct Lung vape look at this Kayfun base.
$4.12 Free Shipping Replacement Base for Kayfun Monster Mini V3 RTA Atomizers (Base (Kayfun Monster Mini V3), Gold) at m.FastTech.com
It is the Kayfun Monster V3 you can do D2L no problem. I used one for about 10 months until i went back to KFL+ V2 base because i missed MTL vaping.