PIERCING THE PROSPHORO
Ideally we would prefer to never pierce the prosphoro.
The reason we pierce is to facilitate the escape of gas which builds up under the surface during the rise and the baking stages. This can cause large bubbles of air to develop which distort the impression. The thin skin over the air cells bakes much darker. This and the presence of the air cell near the lamb, may render the prosphoro unacceptable for use.
Unfortunately, even with our piercings, these bubbles sometimes occur.
How to pierce:-
There are many variations but everyone should keep the 'amno' or 'lamb', the square section in the middle of the seal free from any punctures or defects. We use a thin wooden skewer. In parts of Greece they use only sharpened pieces of dry wood from a basil plant.I have numbered the sequence, in the image below.
We pierce once outside each of the four corners of the lamb and with each piercing, praying "Lord have mercy on Your world, Lord have mercy on everyone, Lord have mercy on all Your people, Lord have mercy on me, the sinner. (1 to 4)
Then we pierce twice just outside the triangular section (left of the lamb) which is for our Panayia, the mother of God, praying "Most holy Theotokos, intercede for us, Most holy Theotokos save us" (5&6)
We pierce twice, to the right of the section for the bodyless hosts of heaven, the martyrs, saints etc, praying for their intercession. (7&8)
Then we pierce above the top lamb praying for our family and loved ones (9&10)
Lastly two piercings (11& 12) below and outside the bottom lamb, praying for mercy for the souls of those who have gone before us. "Lord have mercy on all those who have fallen asleep in the hope of resurrection to life eternal; May their memory be eternal".