My magic fingers (sensitive people needed)

(long time lurker, sporadic poster)

My girlfriend has done quite a few things in her time to get me wondering. But nothing has compared to what happened tonight. As we were fooling around, I touched the back of her neck. I might as well have jabbed her with a cattle prod. From the jitters she produced, I began to think this was a bad thing. Touching her only made it stronger. She went on like this for almost 2 minutes. It was truly bizarre.

When I asked her about it later, she told me it wasn’t exactly bad, but not something I should be doing everyday, either. It’s akin to sticking a battery on your tongue. It tingles, but feels interesting at the same time. She also told me she gets tingly everytime I touch her (not all spastic, though).

Now, what I want to know is if anyone here gets the same way? Were you always like that, or were only certain people able to do it to you? Should I be proud, or worried?
Any input is appreciated.