My electric fence tester consists of a front door type key held firmly between thumb and first finger touched lightly on the fence. The large contact area between key and body and the loose connection from key to fence reduce the shock to a tingle.
I was once packing an electric fence away (25m net, with integral posts), picking each post up in turn into my arms to produce a neat, easy to redeploy bundle.
I backed into another fence (still energised) and got a right 'crack' on my calf muscle and up both arms (trailing all that netting behind me formed a good earth into the lush grass) - the whole lot went into the air! ... and I'm used to getting shocks from the fences.