you can either touch both posts - or the base of your atomiser - one lead on the threads and my favourite - one on the centre hole!
What you are trying to do is to make sure you do not have a short or no connection at all - one = no
vape and the other = death to your battery and depending on your
mod - that too.
I take the possibility so seriously i measure all my
coils at least twice, once on that little black doohdah (technical huh?) and again with a real meter.
Did i mention rampant paranoia - anyway - if you do screw it up this is what will happen...the spring in your Reo will over heat and die and your battery will fall away from the firing pin. New springs are $4 and i have never messed one up yet. But get one just in case!
The spring collapses - it is not reusable, but it will save you from blowing your face off! oh happy day!
You had better fix the short before you go again and most of the time it's a crap coil touching metal - here's one i made earlier - see that bit of wire in the bottom? Not cool!
T