Now, we have the video of a poor bastard who was filling up a gas can when static electricity set him aflame. The video quality is poor, but you can see what is happening. The article goes into more detail.
I have found it helpful to do the stretching exercises my physical therapist recommends. Do some core strengthening exercises, such as the ones highlighted at The Mayo Clinic. By keeping your core strong, your back won't put itself in a position to cause that sciatica pain you are having.