Interesting I haven't been bold yet to try the technique? Would it be like widdling a piece of wood into a point. Methods to prevent stress death, etc?
With a sharp knife you cut the bark all around the trunk at the bottom of the to-be-yinned area. Cut off all the branches above it, leaving stubs. Pull off the bark. Then decide what you want to keep from the rest of the wood.
I would not make a top-yin personally. The tree is way too young and to me it would look odd until you do get some barking of the trunk, in 15 years.