When you filled the tank for the first time and primed the coil, did you just put a few drops in the coil? Or did you put a lot of drops in the coil? Perhaps the sting is coming from the nicotine? I never noticed a slight sting on my tongue, but I do notice it at the back of my throat. If it is too much for you, you should definitely decrease the nicotine level. You can also go with a higher VG percentage. When I was using the Subtank, I tried doing a direct to lung hit, but I'm not sure if I was doing it right. Mouth to lung just feels more natural to me.
I did see some suggestions to drip onto the coil, however, I did not see that in the manual for the nautilus so I did not drip any. But I let it sit all night before even touching it. Was smoking the rest of my analog pack. So it should have been good and wet. The manual for kanger did tell me to and I did three drops. Also let that sit for a good five minutes. I am not getting a high from the 24mg and I am not craving analog big time. Just slightly. So I hate to lower the 24. It might also be the liquid itself. Will have to try another brand. But need to use this first. It wasn't expensive but no sense in throwing it away for such a piddly reason.