I'm terrible at it.
I went to a birthday party during the winter a couple of years ago, and everyone I touched got zapped. I have no idea why that happened. I would zap one person and less than a minute later, while saying hello to another person, they got zapped too. The funny thing was that everyone was complaining, asking me to stop it. Gee, if I only knew how... :p
I wonder if being dehydrated contributes to the zapping.
malu