First of all warm a stemmed whiskey glass.
Put in the sugar and enough hot coffee to dissolve the sugar.
Add the Irish whiskey to fill within an inch of the brim.
Now this is the tricky part: hold a teaspoon curved side up across the glass and pour the cold cream slowly over the spoon.
Do not attempt to stir the cream into the coffee.
It should float on top and the hot whiskey-laced coffee is drunk through the cold cream.