This is a technique similar to CBT in that it is a reliable coping skill based on fact. It is based on the fact that we can only hold so many thoughts at one time. The average is six so I will use six. During a really bad panic attack you might have six symptoms you are focussing on so can't add anything else. If you do you lose something and can often get very scared looking for it. Clumping is putting things that are similar together so they become one instead of many. A phone number is ten numbers 987 654 3210. Try to remember it as ten numbers and you can.t but you can as three clumps of numbers. My technique makes use of this. CBT says change negative thought to positive and this is very well except every positive has a negative and you can open it again. Stacking uses neutral thoughts with no relationship to the trigger or the symptoms of the panic attack. Keep in mind this is a coping skill not a cure, Changing negative thought is. So when you are about to panic or already have you take all the panic thoughts and clump them under one. That thought is "I'm having a panic attack". Instead of six or more negative thoughts you now have only one. There is now room for other thoughts. Before you can open that clump of negative thought you start stacking neutral ones. I start with horses. I think of all the kinds of horses I can think of till I start to lose the first horse thoughts. Then I put all these horse thoughts in a clump and set them aside. Now I think about boats, Different kinds of boats while keeping an eye on my horses. When I have enough boat thoughts I clump them and set them aside and think about flowers. By now because the original thought causing the panic is not related to any of these thoughts it is fading. Keep thinking the neutral thoughts and it will go completely. It usually takes less than 15 minutes.
This is the short version without the technical reason that it works. People that do this say it works for them. Feel free to ask any questions.
Davit.