The technique is simple. As soon as you begin to experience an allergic reaction, with one other hand, apply firm pressure on the center of the webbing between your thumb and index finger on the other hand. Angle the pressure towards the bone that connects with your index finger, and hold firmly for a couple of minutes, while taking deep breaths. Then do the same thing on your other hand.
Some people have been able to arrest severe allergy attacks with this method. I personally haven't tried it, but given that it's an inexpensive, safe and quick way to potentially rid oneself of allergies, I'd be willing to try it the next time it's flower season or I forget that I can't eat wheat.
Too good to be true? Don't not try it for that reason!