King Oyster is unique in that the whole stem is used as it is tender and delicious.
 
King Oyster require particularly high humidity and cooler temperatures in order to pin.  The way to give yourself an edge is to open just the top of the bag so that the block can breathe but moisture is retained.  Then use a fork to scratch and rough up the top surface of the block.  Spray the top of the block 2 – 4 times per day depending on how humid your environment is.  If this is still insufficient to induce pinning then you can add a layer of moistened vermiculite to the top of the block, this is called a casing layer and it will retain moisture at the block surface.  Grows best between 50 and 65F.