1 part of green creme de menthe (or Mint liqueur)
6 part of milk
3 part of Bailey's Irish Cream (or Irish Cream)
Pour the milk first and then the irish cream - the parts are only guesses, I tend to go by color. You want a creamy beige that has only a slight hint of alcohol. Add just enough creme de menthe so as to turn the drink slightly green. Stir it up and serve cold.