If you let the vape come out of your nose first, or nose and mouth together at the same time, you mostly end up with a very thin layer of moisture. Most ppl don't notice it, but the moment they do the nose exhale trick, after two or three drags, their nose starts dripping just like you're having a cold, and its normal.
However, if you're experiencing excessive water or even liquid in your mouth, its not harmful but can be a big discomfort. Here are some reasons why this could be happening :
1) you're vaping at a extremely low wattage, that isn't meant for the coils output.
Let me elaborate, some people think vaping at 10 watt is safer, but they mostly end up getting no vape, little vape, muted flavors or tons of liquid in their mouth. Reason being, while you can vape at 5 or 10 watt, it mostly isn't sub ohming, people will use higher resistance coils or materials, that allows them to do that. Now trying to do the same with sub ohm equipment, will lead to the exact opposite if that makes sense, your coil is not heating up enough, and can't vaporize the liquid itself, giving you either no vape or lots of liquid. Turn your watt/temp up to fix that, not above recommendations when using premade coils of course.
2) flooding your tank/coil
Again, if you're using a regular sub ohm tank, and tend to go above fill line, or in most cases close to the top cap, no matter if low or mid range watt is applied, you will have it in your mouth or your tank starts leaking. As well as a gurgling noise every time you hit the fire button. Leave some space in your tank, during vaping it creates a negative pressure effect, thats created by the air/vacuum of the empty space between top cap and coil/liquid. Without it, it won't operate as intended.
3) too high of watt/temperature
This is a bit different, but I'll post it because you might experience that too/as well. Just like above, but this time, trying to vape at higher watt, if the coil doesn't support it. First thing ppl think of is burned coil or cotton, and the only negative side effect but that's not always the case. You can create what most ppl call spit back, and while it mostly only happens with over flooded tanks or over dripping, when using an RDA, it can occur without all that too, rare but still. You will feel hot liquid in your mouth or your tongue, indicating that you need to lower the wattage/temperature or get a better drip tip lol.
4) duration of your inhale/hit/drag whatever you want to call it
It can occur when your pulls are to long, especially if you have denser vape/clouds. Might want to keep that at 3-5 sec, especially if you chain vape and see how that goes.
5) drip tip
Yes it matters. Sounds stupid but size/shape matters lol.
If you looked at the stuff I wrote above, and all that is not the problem, take a look at your DT. Too small in height can create the same you're experiencing. Same for too narrow or too wide tips. Material matters as well, mostly found with metal tips, they get hot easily and while you might like that, it creates condensated water, that can be as big as a pearl or as small as a little rain drop/sprinkle, that then ends up in you mouth when inhaling, adding more moisture to your vape. Exchange it if you got a different spare and see if it changes.
There's more but that's just a couple of examples. However, you really need to exam the amount of moisture/liquid in your vape. If you feel your lips sticking together, or it feels like sipping a drink, that's to much and my example above might fix it. But if you just have a nice moist flavorful vape with a tiny residue left on your lips or your mouth, then it works as intended.
