Combine the sugar, cinnamon, and cocoa and rim the edge of a chilled cocktail glass with it. Drizzle chocolate syrup around the inside of the glass. Fill a shaker 1/3 full of ice, and add creme de cacao, white chocolate liqueur, vodka, and cream. Shake well and strain into the glass. Garnish with cherries and top with a puff of whipped cream and chocolate shavings.