Ear gauging is a practice in which ear piercings are slowly stretched to accommodate larger jewelry. A typical ear piercing is pierced with an 18 or 20 gauge needle. This creates a piercing large enough for the insertion of most standard ear jewelry, but small enough that it doesn’t stand out when no jewelry is present. This size also heals relatively quickly and easily, for people who decide to abandon their ear piercings at a later point in life.
When ear gauging is practiced, the hole is expanded so that it can accommodate jewelry of a larger size. The smaller the number, the larger the hole, so someone who goes from a 20 gauge piercing to a 10 gauge piercing will have a larger hole. Sizes go to 00 (3/8 inch or 10 millimeters), at which point they are measured in increments of an inch or in millimeters, depending on where one is.
There are a number of ways to accomplish ear gauging, also called stretching. The important thing to remember is that working too quickly can damage the piercing, and potentially cause infection and other problems. Some people like to use tapers, lengths of metal, wood, or bone which are slowly inserted into the ear to stretch it and adjusted as the ear becomes accustomed to the larger size. Other people simply insert jewelry of a larger size, giving the ears a month or two to adjust before stepping up a size. It is also possible to gauge ears by cutting them to enlarge the hole, although this should be done under the supervision of a body modification professional.
( credit: wisegeek )