Rinse the glass with absinthe. Discard. Ignite the tip of a small piece of cinnamon, and place it in a small metal or non-flammable container and invert the glass over top. Allow the smoke to fill the glass while you prepare the cocktail.
In another glass or Boston shaker–muddle sugar, water, and bitters until combined. Gently pour whiskey into sugar and bitters mixture, stir to combine. Add ice and gently stir to chill.
Add a few ice cubes or a whiskey rock in the cinnamon smoked glass and strain cocktail over the fresh ice. Cut a thick peel from a citrus, like lemon or orange, for a garnish, being sure to twist it over the cocktail to express the oils from the rind (the surface not the pith side.)
Run the top of the lemon peel around the rim of the glass and wedge next to the whiskey rock. Be sure to get the aroma of the cinnamon smoke before sipping. Enjoy