Basic Self Defense with the Kubotan Key Chain

I was on the fence about purchasing one of these until this gentleman demonstrated it's effectiveness on me. After this, I was sold and it's now one of my favorite toys.
The Kubotan (sometimes erroneously spelled as Kubaton or Kobutan) self-defense keychain is a close-quarter self-defense weapon developed by Takayuki Kubota. It is essentially a derivation of the yawara (柔?) stick, usually 5.5 inches (14 cm) long and 0.56 inch (1.5 cm) in diameter, slightly thicker or the same size as a marker pen. Attached with a keyring for convenience and concealment, the Kubotan appears as an innocuous key fob to the untrained eye, although it may be considered an offensive weapon in some jurisdictions.
Apart from its size and shape, much of its usage is quite similar to the yawara stick. As with the yawara stick, the principal areas for attacks in self-defense include bony, fleshy and nerve targets such as knuckles, forearms, bridge of the nose, shins, stomach, solar plexus, spine, temple, ribs, groin, neck, eyes etc. The Kubotan is usually held in either an icepick grip (for hammerfist strikes) or forward grip (for stabbing and pressure point attacks). Common uses include hardening the fist (fistload) for punching, attacking vulnerable parts of an assailant's body, and gaining leverage on an assailant's wrist, fingers and joints. With keys attached, it can also function as a flailing weapon. As a pressure point and pain compliance weapon it can attack any point a finger can, but with greater penetration because of the smaller surface area at the ends. For example, a law enforcement officer may wrap his arm around the suspect's neck while simultaneously digging the end of the Kubotan into the small of his back. The officer may also reach around the suspect's neck and underarm from behind and cause pain by digging the end of the Kubotan into the top of his pectoral muscle. One typical pain compliance technique is a wrist "gasket" lock in which the attacker's wrist is captured and sealed around with both hands and the body of the Kubotan laid across the radial bone. Downward squeezing pressure is then applied to the bone to take down the opponent. Its techniques are greatly linked to 'empty handed' martial arts techniques.
In the absence of the Kubotan (and similar weapons like the yawara stick and the koppo stick) improvised versions can be readily found and used in similar fashion. Since a Kubotan is just a rod of material any restrictive regulation would most likely be ambiguous and undefined due to the ability for any rod-shaped item to essentially be used in kubotan-like fashion. Thus, the Kubotan can be replaced by everyday items for example: hairbrushes, pens, magic markers, flashlights, small wooden dowels, even electronic cigarettes. Currently, metal tactical pens are being implemented as similar to the pocket stick.
In the United States, there are few legal restrictions on Kubotans, with the notable exception that Kubotans are prohibited as carry-on items for air travelers. Spiked Kubotan are now specifically listed as offensive weapons on the British government's crime prevention website. Whether a non-spiked kubotan (i.e. a rod) is classed as an offensive weapon in the UK depends upon the circumstances of the case and can be for a jury to decide. In April 2010 actor and entertainer, Darren Day, was found guilty of possessing an offensive weapon (a Kubotan-style keyring) by a Scottish court in Edinburgh.