Conceal the magnet somewhere on your body. For instance, hide it between your fingers. If the magnet is large, consider hiding it under your clothing. Magician Derren Brown suggests carrying a large magnet strapped to your knee.
Borrow a spectator's watch. Ask the spectator if she has ever had a moment in her life that she wishes she could have frozen. Tell her that time is fleeting.
Have your spectator place her hand palm up. Place the watch in her hand face up. Put your hands around the watch and focus on it silently. Allow the tension to build.
Make sure your spectator is looking directly at the watch. If you have the magnet concealed between your fingers, bring them closer to the watch. If it is strapped to your knee, take your spectator's wrist and slowly pull it downwards, bringing the watch closer to your knee. The watch will stop moving.
Pull the magnet away from the watch and it will begin to move again. If the magnet is concealed between your fingers, casually place your hands in your pockets and drop the magnet.