When I was vaping, id sort of inhale it into the lungs, and then breath it straight back out, whereas with cigs I would hold it slightly. Vaping does tend to be harsh, some juices moreso than others.
I personally found 18mg not overpowering, nor particularly harsh. I was smoking a 24mg with wta's at one point, and only after a few days not smoking did it make me dizzy first go (I did find that harsh). But then your mileage may vary. Id certainly recommend a 'lighter' or 'breifer' smoking style than cigs.
"You will be thirsty though as the E-juice is Hygroscopic"
Yeah both glycerol and propylene glycol are hygroscopic. Didnt realise that when I was vapping last.