Add the Skrewball whiskey and angostura bitters to a glass and swirl to combine. Add a large clear ice cube.
If desired, add a splash of soda water to taste: this tones down the sweetness of the Skrewball and is reminiscent of a Wisconsin Old Fashioned. Either way, the flavor is much sweeter than a traditional Old Fashioned. Garnish with an orange wedge and cocktail cherry.