This can happen when too much juice floods the atomizer. I have had this happen when dripping.
Don't overfill cartridges, and when they are full don't draw too hard until some of the juice vaporizes off.
If it's gurgling you're drawing too hard and risk siphoning some juice into your mouth. If this happens just spit it out and rinse your mouth if it makes you feel better.
I've gotten a mouthful of juice (24mg) and am of the opinion it's about the same amount of nicotine/burn as chewing tobacco. So it may make you slightly sick to your stomach if you are not used to this sort of thing, but no permanent harm.
If you overfill a cartridge, you can take it off, and use a cutip, sponge, tissue, rag or whatever you have to blot the excess juice from the filling material. Then reattach and draw gently (and enjoy clouds of vapor) until the excess juice vaporizes off.