Put 1 Scottish measure (25ml) of JD in a lowball glass ('whisky' glass)
fill rest of glass, ideally, with about 200ml of chilled Apple Juice - should be cold enough to not require ice, as this can mask taste. If Apple Juice is not chilled, add 2 ice cubes at most/
Too much JD can overpower apple juice and not taste as nice - if using a larger measure (35ml) it's best to increase apple juice if possible.
This is a very 'drinkable' cocktail if used with the measures suggested, can be easy to that it's 'just' Apple juice and drink more than you might.