Butt plugs (or anal plugs) are sex toys designed to be inserted in the anus and rectum for sexual pleasure. In some ways, they are similar to a dildo, but they tend to be shorter, and to have a flared end to prevent the device from being lost inside the rectum. (Many dildos lack a flared end, and thus it is ill-advised to use such dildos anally, since they may get stuck, requiring medical extraction.)
People of all genders and sexual orientations may use butt plugs.
Unlike the vagina, which is closed off by the cervix, the rectum leads to the sigmoid colon. Objects which are inserted into the rectum can therefore potentially travel up into the bowel: the flared end on a butt plug exists to prevent this.
In addition, the lower bowel above the rectum is easily perforated. For this reason, butt plugs tend to be shorter than dildos, and their range in size tends generally to be a variation in circumference. They must also be very smooth to avoid damaging the rectum or bowel. In order to get them into the rectum, they most commonly have a general profile of a round-ended cone which then narrows to a "waist" which locates itself at the anal sphincter, with the flared part outside the body, preventing the butt plug from slipping further into the body. The sphincter muscle will hold the plug in place by the waist, preventing the plug from slipping out unintentionally.
Butt plugs are often used covered by condoms for hygiene, and to allow for the easy disposal of any feces that they may come in contact with. Nevertheless, they should not be shared with other people, due to the risk of blood-borne diseases, including HIV that can arise from the transfer of body fluids from one person to another. These should also never be used to stimulate any area other than the rectum, though they often are.
A butt plug is not necessarily confined to only anal stimulation. Butt plugs may be transferred and rotated to and from the rectum, vagina, and mouth. This is quite an unsanitary way to engage in sexual stimulation unless certain precautions are made; such as cleaning the butt plug in an anti-bacterial fashion by e.g. alcohol, the vagina being covered in plastic wrap, the buttplug being covered by a condom (which is removed before any transferring takes place), and other various methods. If these measures are not taken, fecal matter may be passed to other parts of the body causing sickness, infections, and a malodorous scent. Though these ill side effects may take place, some butt plug users will still take this risk.
Butt plugs come in a variety of colors, shapes, sizes, and textures. Some are designed to look like penises, while some are ribbed or wavy. The majority, however, shaped as shown in the picture above, with a thin tip, which is wider in the middle, a notch to hold it in place once it is inserted, and a flared base to prevent complete insertion into the rectum. Some plugs are designed (long, flexible and curved) to penetrate the sigmoid colon.
Butt plugs are made of a variety of materials, the most common being latex. Other materials used include silicone, neoprene, wood, metal, glass, stone, and many other materials. Silicone is a particularly good material, as it can be sterilized in boiling water.
There are butt plugs that "ejaculate" by squirting water or other viscous fluids into the rectum. There are also vibrating butt plugs, and butt plugs that can inflate and expand. Some butt plugs are specifically designed for men and stimulate the prostate. Other butt plugs are manufactured with long hair or simulated animal tails attached to the base for use in human pony play or other animal fantasy role play.
Butt plugs can be moved in or out for pleasure; for this type of activity ribbed butt plugs can increase pleasure. They can also be worn continuously (or be lockable) for long periods of time.
When wearing butt plugs and holding the anal sphincter open for very long periods of time one should take care, as this practice could potentially decrease the elasticity of the anal sphincter muscles. The BMEzine risks glossary states that "The process is similar to earlobe stretch except that the 'jewellery' is not worn all the time" and that there is no harm done to the function of the sphincter when stretching is done carefully. However, loss of anal muscle tone can result in fecal incontinence. Kegel exercises can help restore normal, non-assisted sphincter function, in such cases. As long as the user warms up properly and uses proper lubrication, the risk of damage is minimal.