Technique is what separates a good drink from a great one. Both shaking and stirring are valid techniques—depending on the effect you want. Shaking will aerate a drink, make it cold, and leave it more diluted than stirring would. Use a shaker when you need to ensure a drink is fully combined. Stirring, on the other hand, will keep a drink clear and cold. When done properly, it will prevent little bits of ice from diluting your drink.One thing you should never do, though, is shake a carbonated drink. However, it may be appropriate to shake the base ingredients and top them with the carbonated beverage.
Here is what I do. Get a cup of whatever your favorite coffee is. Add a shot of whatever your favorite whisky is. Enjoy sipping slowly. My favorites are a cup of Ethopian coffee with a shot of bourbon. Something like Bulleit, or Knob Creek even.