First you or a friend will have to create a Friends League then have the other one join it. To create a Friends League you must go to the Main Menu -> XBOX LIVE -> FRIENDS LEAGUE -> CREATE A LEAGUE then you will want to customize the league but keep the names etc. as simple as possible and don't bother giving it a password. Most of the settings don't matter but you will want to set the max DNF as high as possible to ensure your friend can join your League, you will also want to play at least 2 matches to return the favor to your Friend once you have the achievement and you will want to make the Half Length 2 minutes to get the achievement quicker.
A friend can join another's League by going to the Main Menu -> XBOX LIVE -> FRIENDS LEAGUES -> JOIN A LEAGUE then by entering the relevant search criteria and selecting the right league when it shows up.
After someone joins their friend's League, then you are ready to play a Friends League match. To do this go to Standings and select the other person's name, now choose Invite to Game and you will be taken to the team select screen whilst your friend receives a standard Xbox LIVE "Person wants to play" invite. When your friend joins advance through the menus and have whoever wants the achievement win the match.
This achievement requires Xbox LIVE Gold and an "Online Pass" or the use of your 7 day Online Pass free-trial.