Brief stimulation of the upper lip with the tip of a nylon thread frequently produces an "afterglow" sensation that may persist as long as several minutes after cessation of stimulation. The duration of afterglow is increased by strong suggestion, and decreased by vibration of the skin prior to stimulation. The afterglow may be followed by a period of acute "awareness" of the area, distinctly different from the stimulus and afterglow sensations. The afterglows produced by a warm stimulator applied to the back often well up into a painful sting.