A "7 and 7'" is a mixed alcoholic drink served in a highball glass with ice, crushed or cubed. It is made with one jigger of the Canadian Blended whiskey known as "Seagram's 7 Crown" and the Coca-Cola Company's lemon-lime flavored carbonated soda drink called "7-UP". After adding the alcohol, top the glass off with the 7-up and toss in a lemon or lime twist ( which releases the oils in peel) and serve. Do not stir...allow your guest to do that.
It can also be called A "Double 7&7", meaning two portions of alcohol are added instead of one. Hope this helps!