Static buildup is often caused by the friction rubbing of your bodies skin and hairs against various clothing, or from various clothing to verarious other cloths (i.e. carpets, fur, rugs, etc..), which basically builds up a static charge on your body. When you come in close contact with someone or something that does not have a charge of equal field strength, or has an opposite charged field, or a charge that is of much greater field strength than yours, then the two fields will attract each other and discharge.
This static build up and discharge occures pretty much constantly on your body each and every day, however the voltage and currents produced are usually so small that you do not notice it.
To make a charge and discharge it at will, you would need to create some sort of static field generator. However, controlling where the static field will discharge would of course be the much more complecated thing.
Good luck. Think Safe!