How do you fill an e-liquid tank?
It’s like fueling your car, but cheaper. Depending on your model, you fill from the top (top-fill) or the bottom. The open secret: never pour liquid into the center hole (the chimney), or you'll end up drinking your juice instead of vaping it. It's not toxic in small doses, but it tastes pretty bad.
From a technical standpoint, make sure to tightly close the silicone plug or top-cap to maintain air pressure inside the tank. If air leaks in, liquid leaks out... usually through the air intakes. Always leave a small air bubble; don't fill it to the brim to avoid liquid spit-back.