A piercing through the clitoral hood. It is similar to a horizontal hood piercing, except the triangle piercing passes under the clitoral shaft rather than above it.
As with all female genital piercings, the triangle piercing is anatomy dependent and not all women can get one: the clitoris must sit high up in the hood, so the piercing has room to pass under it and not hit the shaft. If the needle does hit the shaft, there is a good chance of nerve damage and excessive bleeding. Because of the necessary and relatively uncommon shape of the clitoral hood, this piercing is rare.
It is usually pierced with a 10–14g captive bead ring, to make cleaning easier. Once it heals, either a barbell or a ring can be worn in it, but even if a ring is kept a new one with a smaller diameter is often worn. Many women find that the more they stretch the piercing, the more pleasure they can derive from it.
The piercing hurts quite a bit; about the same as a standard hood piercing, but not as much as a clit piercing. Because of the pain, some women opt for a local anesthetic such as xylocaine, but as many if not more women do not. The pain, while intense, lasts only for three seconds (if the procedure is done correctly).
So how do the ladies like it? "My orgasms have become nothing short of earth-shattering," says one woman in one of the piercing experiences archived by BME. The piercing is often the favorite of women with other genital piercings, since it provides stimulation to a side of the clitoris that almost never gets stimulated.
Healing time ranges from eight to twelve weeks. While it's healing (and preferably afterwards, too), the piercing should be kept far far away from places where bacteria like to live — washcloths, dirty hands, tongues, swimming pools, etc. Sexual activities (including masturbation) should be held off until around three weeks after the piercing is done.
No personal experience in this one — women's opinions paraphrased from BME's collection of piercing experiences. The quote is from the "And now I jingle when I walk..." experience.