Hi Dave and Tammy, Ed posted some great ref photos. I tried to do this on a KV-2 build a while back:
A pyrograph or solder would have been good but for this I just used a bullet head nail too. I held it in some pliers and heated the end over a flame then carefully pushed against the plastic. It naturally forms the ridges and deformations as it penetrates, but as always it's good to practice on some scrap plastic first.
I think I recall that wispy strands of plastic sometimes formed, these were just cut off as some impacts were worked a little with a sharp blade.