Things You'll Need
Instructions
Select "Private Match" from the COD MW2 multi-player dashboard.
Press the dashboard button on your Xbox controller. This is the big round button at the center of the controller.
Toggle down to the second menu option titled "Friends." Again, toggle down to your desired online friend, press the "X" button and choose "invite" to invite the player into your private match. Press the "B" button to leave the dashboard and return to the Private Match screen.
Choose "Game Type" from the private match dashboard and select "Domination."
Press the select arrow on your Xbox controller (left of the dashboard button), to adjust the game settings. Select "Unlimited" for score and kills, disable Killcam and "Allow" for the "Join Session in Progress setting. Press the "X" button to save the settings, returning you to the private match dashboard.
Select "Start Match," ensuring both players are on the same team. Once the match counts down to zero and each player is able to walk around, player one presses the dashboard button on his controller. Once on the dashboard, toggle down to "Friends" and press the "X" button when player two's gamer tag is selected. When player two's profile area opens, toggle down to the "Join Session in Progress" link and press "X." At this point, the host will migrate to player two and a new count down will begin.
End the game once the host migration count down ends. This step is done by player two by pressing the "Start" button and selecting "End Game." When both players are returned to the private match lobby, toggle over the game type section, press "X" and toggle over (without pressing "X") the "Free For All" game type. Remain there while player one checks the private match dashboard to confirm the game countdown timer has begun.
Allow the countdown timer to expire and the special game mode will start. Players may join in randomly. Continue playing the match for as long as desired to rack up a large amount of XP.
Communicate with the other team that a tactical nuke needs to be dropped when you are ready to end the game, Instruct a player to get 25 kills in a row without being killed to unlock the nuke. That player presses the "Up" arrow on their controller and presses "X" to drop the nuke.