Most tongue piercing is performed using a straight barbell in 14ga to 10ga using a standard needle piercing procedure. Other piercers have performed this piercing using a scalpel, cutting lengthwise along the grain of the tongue to install 2ga or 0ga initial jewellery, usually a Teflon plug or even wooden jewellery other people choose to stretch to these sizes. In the larger sizes, people may choose to wear hollow barbells with smartie beads to reduce the weight and stress on the surrounding tissue.
Tongue piercings carry almost no infection or risks directly related to the piercing (like cancer), but they do carry a large risk of tooth chipping after all, if you bite down hard on a steel bead, what do you think will happen to your tooth? However, the risk of chipped teeth can be almost totally eliminated by wearing properly sized jewellery. For healing and initial piercing, the tongue jewellery should be 50% longer than the thickness of the tongue (normally this is 3/4"), but once healed it is very important that a shorter bar be installed.