Hi there,
Glad you like the experience - I felt the same way as you - went bonkers round the house - wife thought I'd been electrocuted!!
Anyway, re the gurgling sound; as Kit says above this is the '
juice' bubbling on the heating element. Great up to a point.
When the battery starts to loose some of its charge, some of this liquid will escape the chamber and will be drawn up the sides of the tube and you could get some in your mouth. Trust me on this - it will happen to you at some point and is not pleasant at all!!!
When I get a lot of gurgling, I take out the cartridge and replace it with just a mouthpiece and fresh battery. I then smoke the e-cig without the cartridge until the gurgling drops off.
Re the other sound you refer to!!!! Ahhemm, well I have tried to replicate it and believe that the mouthpiece may not be fully pushed home - air could be escaping around the sides.
Could be wong though as I haven't experienced such a noise as I insist my cartridges are fully potty trained before purchase!!..
All the best, and if this is your first e-cig, then congratulations, you bought a real belter from the off.
Jerry