Two weeks ago I participated in a seminar at my dojo where a so-called Kubotan or self-defense stick was introduced. I had never heard of that thing before. In two sessions, we got some background info and theory, then quickly went on to the practical part, practising punching and grappling techniques with this tool.
My personal impression is that this tool (I won't call it a weapon because even here in Germany it is not considered a weapon by the law) can be very useful in a self-defense situation. But I see it more or less as an amplifier: if you can punch, then it will add power to your punches. If you can grapple, you can use it to amplify your leverage on your opponents joints. If you know how to attack pressure points, you can apply a lot more pressure to them with a Kubotan than with your bare hand.
Are there other ways a kubotan can be used in self-defense?