I don't bother to sharpen the edge of the ribbon.
I can't see that it serves any purpose because the groove that the ribbon fits into is already incised by the piercing tool.
I do bother to form many little grooves along both sides of the ribbon though.
These little grooves running from one end of the ribbon to the other, become trapped by the wood when the wood is wetted and its grain tries to return to its former position.
To form the little grooves on the ribbon I wear a pair of leather gloves to keep from cutting myself.
I then hold a very fine toothed file so that the ribbon will pass over the edges where the file faces meet.
Laying one end of the ribbon over the corner of the file and pressing the ribbon against the corner with my gloved thumb, I pull the remainder of the ribbon over the edge of the file with a pair of needle nose pliers.
Once one end is pulled thru, I reverse the ribbon and repeat the process on the other side.
After the wetted wood dries, the grooves on the ribbon and wood grain lock the ribbon in place.
No glue is needed.