Chill gin on ice in a tall glass.
Fill with Tonic (or Soda water).
Add a Lemon wedge (squeezed and thrown in).
Finally drop in the candy (originally made with "cherry certs" but
other candies will do.
"Scotch mints" add a nice Christmas twist).
As the candy dissolves the drink slowly sweetens, the candy also
forms pretty bubbles in the tonic water.