From 'the Book of the Cult of the Infinite Without'

Let the Aspirant stand upon the edge of a precipice in act or in imagination. And let him imagine and suffer the fear of falling. Next let him imagine with this aid that the Earth is falling, and he with it, or he from it; and considering the infinity of space, let him excite the fear within him to the point of ecstasy, so that the most dreadful dream of falling that he hath ever suffered be as nothing in comparison. This is the forth practice of Meditation (Liber NV)