In one sentence, describe what the following article is about:

Place the tip of the stem at the tip of your tongue.Because the stem is lying parallel to your tongue, the motion of pushing up will naturally bend the stem in half. Keep pushing your tongue up until it presses the stem against the roof of your mouth--keep it pressed there. During this step, your lips should remain closed. Hold the stem between your front teeth, where it should form a loop with the ends in an X-shaped crossover. This motion should leave the tips pointing toward the front of your mouth. While still biting down on the stem with your front teeth, locate and push the longer end of the stem through the loop. Keep biting down on one end as you pull the knotted stem out of your mouth by the other end. This will tighten your knot and keep it intact before you reveal it. Present the tied stem with a flourish, holding the loop so everyone can clearly see the knot.

Summary:
Lay the stem lengthwise on your tongue and push your tongue up slowly. Bite down gently until the two ends of the stem cross over. Use the tip of your tongue to push one tip through the loop. Grab one end of the stem with your fingers.