Warning: Do not try this at home. Or do. We won't judge you.
Also, please note that this is a highly experimental and utterly useless technique for removing hair. We mean it. Completely and totally useless.
But if you insist, here's a step-by-step guide:
1. Locate the offending hairline.
2. Prepare your scalp for battle with a liberal application of hairspray.
3. Engage the trimming action with your razor or trimmer, taking care not to cut yourself.
4. Repeat steps 1-3 until the desired level of baldness is achieved.
Want more information on other forehead surgery techniques? Eyes on the prize, or Eyelid-surgery: The Art of the Steal.