3- Find a length of metal piping 5cm diameter and sharpen one end.
(I also used 7cm and 4.5cm for Flying Panda and mini motu sized holes)
I could only find plastic pipes, which I sharpened with sandpaper:
I found that I had to go through the sandpapering process before each and every hole.
4- Punch the hole using your full body weight and a gentle twisting action:
5- Slice the best looking "holes" as padding pucks: