One of the most common questions by those who are new to stretching is whether to use a single flare or double flare plug. Both of these types of plugs have their benefits and drawbacks, but they are not meant to be used in the same situations. Single flare plugs are best for the initial stretching. Once the new gauge has been comfortably reached, a double flare plug can then be used.
The flare of a plug is a raised lip that prevents the plug from sliding in or out of a piercing. A single flare plug only has this lip at one end. The other end is straight, so it is easy to fit into a piercing. After a single flare plug is inserted, it is held in place by a rubber O-ring around the back.
A double flare plug has a lip on both ends, so one of the flares must be forced through the piercing when it is inserted and removed. Because of this, double flare plugs should only be used after the piercing has been comfortably stretched to the gauge of the plug. If you are in the process of stretching, the flare can tear or otherwise compromise the piercing because the measurement of the gauge is taken at the center of the plug.
Single flare plugs are perfect when you are first stretching a piercing to a new gauge. The plug can be easily slipped into place, and the O-rings are simple to attach. However, care should be taken to avoid single flare plugs that have an indent for the O-rings. The best single flare plugs are completely smooth past the flare. Even a slight indent can irritate a piercing and cause bleeding. The downside of single flare plugs is that they are not as attractive as double flare plugs from the back. In addition, some people do not like to go through the trouble of attaching the O-rings, which can fall off and get lost.
Once your piercing is properly stretched, a double flare plug can be used. Some people prefer a type of double flare plug known as a saddle plug. A saddle plug has smoothly tapered flares instead of flares with hard, straight edges. This type of plug is easier to insert and remove, but once inserted, it stays put. Saddle plugs are becoming more popular every day, and they can be made from a wide variety of materials.