Hi, I have been struggling with my device for a while. I started vaping a couple of years ago using an ego twist with a small carto tank. It worked great for a while but of course I wanted to upgrade. I bought an Atlantis tank and istick 30. I just couldn't love it, I didn't like the big airy draws. I sold it to a friend and bought a nautilus mini and istick 20......trying to find a happy medium. I really like the way it works but I have really bad mouth issues. The longer I use it(within hours) the more burned that my mouth gets. It is like I have burned my mouth with hot liquid, not in one spot but all over. I drink lots of water, use biotene, use liquids with no artificial ingredients and with a higher vg. I recently went back to my ego twist and bought a small aspire tank and my mouth is much better. After ALL of that being said I was wondering if anyone else had ever had a problem like this. I have 3 minis and was also wondering if I changed the kind of coil that I use would it help. I am using the coils that came with them. It just seems like the bigger device is what is causing my problem. Thanks so much for the help!