I enter this non-descript space that is neither indoors nor outdoors. The ground is flat and beige, and there is a wall. Near the wall I notice a giant centipede, a tropical sort with a red stinger tail and about a foot long.

I feel revulsion and find myself horrified by the centipede, and then notice that I'm closer to the centipede, I think I've walked towards it. The centipede rears up, standing on a few of it's hind legs and arcing towards me, like the way a cobra stands up when threatened. I get the sense that the centipede is aggressive. At this point I notice that I'm completely nude, and my legs are standing apart slightly and my penis is hanging down. The centipede strikes me on my penis, delivering a whopping sting! It feels like a tremendous electrical shock through my whole body and is accompanied by a flash of light. I'm so shocked that I wake up from my dream. I end up wide awake for 3 hours after, not so much because it was frightening like a nightmare, but shocking leaving me alert and awake.

Background: I'm mid 30s male, married in a great relationship, and with a 1 year old son. Sexually, I would say that I'm satisfied and comfortable, but like many I probably wish for more.
Centipedes have always been the pinnacle object of fear for me. When I was very young I saw a preview to a chinese or indian horror movie that involved giant centipedes, which terrified me, and has stuck into my brain somehow. Also, growing up in the tropics I encountered these creatures from time to time and was always petrified by them. They are the only creature that I can say I'm uncomfortable with - spiders, snakes, rats, all the traditional scary stuff doesn't faze me one bit. In fact I really love them.

Ok thanks for your insights, I'm completely ignorant in the world of symbols and dream interpretation, so I appreciate yours!
My first post didn't seem to work, so I hope I didn't accidentally double post.