Self-bondage

Self-bondage refers to the use of restraints on oneself for erotic pleasure. It is a form of erotic bondage which can be practiced alone.
Self-bondage is characterized by experimentation and ingenuity, and can be riskier than conventional bondage. Self-bondage requires use of techniques for self-binding as movement becomes increasingly restricted as more restraints are applied, and also requires a reliable release mechanism. Many types of bondage equipment can be applied before the one that restrains the hands. For example, leg irons can be applied, as well as gags, blindfolds, etc.
For many of its practitioners, the added challenges and dangers are a part of the appeal of self-bondage, who often devise elaborate self-bondage schemes and release mechanisms, both in practice and in erotic fiction.
Risks.
Self-bondage is considered a higher-risk activity than many other BDSM practices — particularly when combined with autoerotic asphyxia — and has led to a number of recorded deaths. The death in 1994 of Stephen Milligan, the British Conservative MP for Eastleigh, was a case of autoerotic asphyxiation combined with self-bondage.
Self-bondage has all the risks of physical restraint and sexual bondage, with the added factor that should anything go wrong, there is no-one to effect a rescue. For example, if blood circulation cuts off sensation in limbs, the planned escape mechanism may not be usable.
Types.
Self-bondage can be either "strict" or "sensual".
Sensual self-bondage.
In sensual self-bondage, escape from restraints is simple and available immediately, if desired. For example, the keys might be within reach or the knots loosely tied. The chief aim is the sensation of immobility and of constrained movement.
Strict self-bondage.
Strict self-bondage requires that the means of escape be unavailable until the lapse of time before the release mechanism activates itself. This feature of strict self-bondage makes it potentially more hazardous, but some practice it for the greater sense of helplessness it creates.
Emergency intervention.
A compromise position between safety and strictness allows for a backup release mechanism that is available immediately, but carries with it some penalty or cost with its use. For example, keys could be placed in a bucket of paint. The person in self-bondage can escape quickly if necessary, such as a fire breaking out, or excessive numbness of limbs. However, the annoyance of cleaning up the paint afterwards would coerce the person into waiting for the main release mechanism to come into effect if he or she were merely bored or uncomfortable. Another penalty may be the need to contact somebody, with the penalty being having to explain what has happened.
Release mechanisms.
Many release mechanisms are used in self-bondage to allow the practitioner to escape the restraints after a period of time. There are various trade-offs to be made between ease of use, reliability, precision of timing, cost, and so forth. There should be several mechanisms available, thus ensuring redundancy and safety.
Emergency backup.
There are also a number of release mechanisms designed to be emergency backups. The idea behind these release mechanisms is that triggering them will cause something undesirable to happen, and thus are only used in situations where death or serious injury could occur otherwise.
Techniques.
Apart from release mechanisms, self-bondage poses a somewhat awkward problem of getting "into" bondage, especially when using rope. What might be a relatively simple matter for couples can be considerably more complex alone.
With rope, the main difficulty is tying the hands in a way that is not easy to untie. One common solution is to use a "cinch noose" — essentially a kind of slip knot — together with a "coil" (a loop of rope). The wrists are placed through the coil with the cinch noose between the wrists and around the coil. To achieve a basic hogtie position, the cinch noose is tied to the ankles. With pressure, the noose tightens the wrist coil, securing the hands. It proves very difficult to escape from, and usually a knife or scissors is required to cut free.
Equipment that can be tightened only, and not loosened, often has application in self-bondage. This includes handcuffs, zip ties and ratcheting pulleys.
Commercial equipment.
While for the most part self-bondage is performed using ordinary and easily available equipment (indeed, it lends itself to impromptu adaptation and a "do it yourself" approach), a few commercial products have appeared — in the United States and United Kingdom for the most part — catering for the self-bondage practitioner.