A lot of people experience this issue, and frankly Joyetech doesn't have a concrete answer, here is what they say "Seems that the coil is over wet, kindly suggest you hold the tank upside down, and swing it swiftly." In my opinion if you consider the price of the tank that means that the tank is a piece of garbage. If you want to complain or hassle Joyetech about it you can do it here:
http://social.joyetech.com/showthread.php?pid=9315 (I know that I am not supposed to direct anyone to another forum but that's not a vaping forum per se, It's really a manufacturer service site).
Anyway as for your issue I would love to see you swinging your mod everywhere (just don't do it towards other people or you will bathe them on e-juice). I don't know why the whole thing reminds me of a catholic priest in a blessing with holy water, LOL.