A tongue piercing is a piercing through the tongue. A single piercing in the centre of the tongue is the most common form but multiple piercings (either one in front of the other in the center or one on each side of the tongue) are also possible. Piercings should be placed carefully to avoid hitting a nerve or, more commonly, a vein. The piercer should also take into consideration the tongue "webbing" (the part under the tongue that connects the tongue to the bottom of the mouth) and the position of the potential piercing in relation to teeth to lessen the risk of damage. Off-center piercings can be more complicated as they pass directly through muscle (where as center piercing pass through the space between the two muscles) so should only be performed by experienced piercers.