After some discussion with Marcel, I have decided to add another output to the experience: temperature. The little white square at in the top corner of the image is something called a Peltier device - they often use it in mini fridges for example. When you run electricity through it, one side of the peltier gets extremely cold, and the other extremely hot. Using an H-bridge (a device which is able to swap the polarity (+) (-) of the electricity) I am able to create both hot and cold sensation on one specific area of the body.