This is a common problem and usually caused by a flooded coil and/or a low-powered battery or a battery that is running low on power.
Bear in mind too that most e-cigs generally require a lighter draw than a traditional cigarette.
See also our article about e-cig tank flooded which will give you a lot more detail about how the liquid ends up in your mouth if it can't turn into vapour fast enough.
In the meantime you will need to clear your coil/tank parts of excess e-liquid:
How to clear the excess liquid without emptying the tank (if it has liquid in it) ...
1. Remove the clearomizer tank from the battery - taking care to turn the clearomizer sufficiently upside down to stop the liquid running out as you remove the battery
2. Wrap a paper towel around the battery end of the clearomizer while its upside down and blow through the mouthpiece - again without turning it upright and spilling liquid
3. The excess liquid in the central air flow tube will come out onto the paper towel as you blow. You may need to blow a few times to ensure the tube is clear
Sub-Ohm coils
If you’re using a sub-Ohm coil and you’re getting liquid in the mouth, this example of what not to do with the likes of the Eleaf Melo, may prove helpful.
Firstly, ensure the power (ie the wattage or the voltage) is in the correct range for your coil.
In the case of the Melo 0.5 Ohm coils it’s probably circa 25W. The Melo is designed to match the Eleaf iStick 30W mod which has a range of 5-30W but if you set the wattage too low the liquid cannot vapourise, and instead it will gurgle away, perhaps get darker in colour, and you’ll end up with it in your mouth or seeping out wherever it can because it has nowhere else to go every time you press the fire button.
You also need to use a good quality e-liquid with more VG than PG (VG is thicker than PG and produces a lot more vapour).
Be aware that 6mg (0.6%) nicotine is probably an absolute maximum strength e-liquid to use with many sub-Ohm coils.
If you can’t take the hit from the increased vapour from the VG content of the e-liquid, turning the power down will cause more problems than it solves, instead you need to reduce the nicotine strength.
In addition to this, when you press the fire button you need to inhale directly into the lungs ('lung it'). Sub-Ohm vaping, which usually has a looser, more airy draw, is designed for direct lung inhale, as opposed to the more traditional mouth to lung inhale.