I secure the looped lily grass to the aster boutonniere with a short pixie corsage pin. At this point, I don't want to use florist tape, since I'm going to use decorative wire to attach the grass to the boutonniere.
Pin the pearl headed pin in an upward slant, burying as much of the pixie pin into the boutonniere stem as you can.
Handle with care, since it is easy to split the lily grass unintentionally. Cut the long end of the grass short at a point angle to match the natural point of the grass on the right side.