Most demonstrations incorrectly focus on friction.
Also, the nature of matter and the fundamental reasons for charge conservation are usually ignored. The following demonstrations are my attempt to fix these problems. Pull a couple of long strips from the roll, about 20cm each. Hold them up by their ends so they hang downwards, then slowly bring them side by side. If you try to force the dangling lengths of tape to touch together, they'll swerve and gyrate to frustrate your efforts.