When the fluid is heated in the atomizer, not all of the produced vapor is getting to your mouth. Part of the vapor condenses along the path in your cartridge, already. There is a small barrier to trap this condensate inside the whistle tip of your cartridge, so to prevent fluid from getting into your mouth. This fluid trap, however, can only hold a certain amount, just some drops. Once this trap is filled, fluid will leak into your mouth, no matter how hard or light your draw.
Fluid may also get there due to overly filled cartridges. You want to have the filler moist, but do not want free floating fluid. It’s critical that your cartridge is not overly filled when you push it into the atomizer. When you put an overly filled cartridge into the atomizer, the filler gets slightly squeezed and liberates the excess fluid. Also, when you have new cartridge, keep the device upright, so that fluid won’t leak from the container and flood the fluid trap.
The following procedure will clean your cartridge from the excess liquid that is getting into your mouth. I’ve read from your opening post, El D, that you may have to instruct your helping hand for it. I assume that you have the usual 801 cartridge, consisting of two main pieces, a) the liquid reservoir and b) the mouth piece.
1.) detach the cartridge from the atomizer, 2.) use some kitchen paper to dry the outside of the liquid reservoir, 3.) pull the liquid reservoir out of the mouthpiece, 4.) wipe the lower part of the liquid container from the outside, 5.) use kitchen paper to dry the inside of the mouthpiece down to the whistle tip (that’s where most spilled and condensed liquid gets trapped), 6.) put the reservoir back into the mouthpiece to reassemble the cartridge, 7.) wipe off excess fluid from within the atomizer (only wipe the upper part where you put in the cartridge, and don’t let the kitchen paper come in contact with the metal mesh deep down), 7.) put cartridge back into the atomizer to reassemble your pen. 8.) Enjoy vaping without spitting fluid.