Pour Campari & Grapefruit in the rock glass,with plenty of ice,stir & gently pour and stir Tonic.
Garnish is up to you,I often use Grapefruit peel,instead Orange.(Note:this is very popular drink in Tokyo!!!!)
Leave some comments about the Spumoni
Found it in a can over in Japan - If you like your drinks bitter, this is a good one.