On the days I took photos of the parade, I arrived at the shrines at 5:30 or 6:00 a.m. There were already several dozen people there each day. Most people wore all white, while those who would undergo the piercings would wear a colorful traditional garb. It was pretty clear that the participants were getting ready for their ordeal, as they walked around, shaking their heads and often murmuring to themselves.
When it was time to get ready, the man would sit on a plastic chair. Another man, usually one bearing the scars of having done this in the past, would stand behind him and hold his head with both hands. Another man had an eighteen inch cone shaped metal rod with a point on one end. He cleaned the rod with alcohol, then poured some kind of oil on it. He then pushed the rod through the participant's cheek, creating a hole up to two inches in diameter. Next he would withdraw the rod, and put in another object, such as a wrench, pistol barrel, knife, saw blade, etc. Usually they would then do the same thing for the other cheek.
Most of the participants were pretty stoic when it was happening. One guy left no doubt that it hurt as he yelled out 'uh uh uh" many times.
It was pretty crazy when this happened, as many photographers, both falang and Thai would gather around and try to take photos. If you weren't at the right place at the right time, it was difficult to get the shot of the piercing happening. Everyone wanted to get the photograph, and the crowds were sometimes 5 or 6 deep.
I really lucked out one time. I having limited luck getting a photo of one piercing, when someone came over and placed a plastic chair within arm's length of me and a man in a traditional outfit sat in the chair. I knew that this was my chance. I actually stood in between the handles of one of the little platforms that are carried on the shoulder and display idols. From there, I ended up getting quite a few shots, even some as it actually pierced the cheek. It was kind of cool.
The wounds certainly did bleed, but there wasn't really a whole lot of blood around. There were people around who would dab off the blood when it was happening. As they marched, there were also people with each participant who would dab off the blood.