The Stimulating Compass is a spell used by magicians on demons who do not follow the orders of their master. The spell causes lightning to erupt from the 5 corners of the pentacle and attack the demon inside. This spell, just like any other spell, can be reversed by the demon if the demon in question knows the magician's birth name.
Nathaniel once used the Stimulating Compass on Bartimaeus. Arcs of electricity coursed over Bartimaeus's muscled, bare-chested body, and the force of the charge was so great that Bartimaeus was actually lifted off his feet, yelling in agony. But, Bartimaeus was at an advantage, though in pain, he managed to murmur Nathaniel's name and performed the Counter-curse. Instantly, the spell left him, and he slumped back into the floor. According to Bartimaeus, he had been on the receiving end of the Stimulating Compass many times before, and the magicians took great pleasure in seeing the ever-confident, cocky, quick witted Bartimaeus airborne, squirming, as they electrocuted him.