The technique is extremely simple. You look at one person's eye while they look at one of yours, and without taking your eyes off their eye you both attempt to see the clearest (albeit unusual) visual image you can. Within a few seconds (usually) you will both notice changes in the appearance of the other person's face. At first you will most likely see a blurry image, then "distortions" of their normal features. As you continue to concentrate, blinking whenever your eyes need wetting, these distortions will become organized into recognizable facial features, either "hallucinatory" or clearly the features of some other person than the one you sat down with (not exactly a run of the mill experience, eh?). The most important aspect of these perceptions is that the visual changes occur to both participants at the exact same time and have the same level of intensity.