If the hand you put in the tank had a small cut on it then you will experence a 'tingle' from the saltwater interacting with the wound. Depending on the size of the cut the tingle can excliate to pain.
Dont be worried about the placment. Shoot just put it in at an angle. Its just a titanimum rod. Titanium is used as its corosive resistant and a good conductor. Many have plugs on the end that you put into the wall. The AC
leads are made of plastic and the grounding lead is metal. Others have a simple screw loop that you screw to the outlet faceplate screw.