To begin, fill a mixing glass with ice cubes. Add the tequila, sweet vermouth, dry vermouth, and Campari to the mixing glass. 

Stir the ingredients together until they are well combined and chilled.

Next, strain the cocktail into an old-fashioned glass filled with ice cubes. 

Add a dash of Angostura bitters to the top of the cocktail. 

Finally, garnish the drink with an orange peel or twist.