A tongue piercing is a body piercing

Body piercing

Body piercing, a form of body modification, is the practice of puncturing or cutting a part of the human body, creating an opening in which jewelry may be worn. The word piercing can refer to the act or practice of body piercing, or to an opening in the body created by this act or practice...

 usually done directly through the center of the tongue, and is the most popular piercing site in the western world after the ear and nostril.

There is a history of ritual tongue piercing in both Aztec

Aztec

The Aztec people were certain ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl language and who dominated large parts of Mesoamerica in the 14th, 15th and 16th centuries, a period referred to as the late post-classic period in Mesoamerican chronology.Aztec is the...

 and Maya

Maya peoples

The Maya people constitute a diverse range of the Native American people of southern Mexico and northern Central America. The overarching term "Maya" is a collective designation to include the peoples of the region who share some degree of cultural and linguistic heritage; however, the term...

 cultures, with illustrations of priests piercing their tongue and then either drawing blood from it or passing rough cords, designed to inflict pain, through the hole.