Supreme Commander 2

To add to RagnaroK's guide, the easiest map to do this on is Mirror Island (2v2). Reason being is that the AI is right next to each other, so if you assign a cheating AI next to the easy AI, it'll be decimated in no time.

You can easily get the Rushin' Front achievement via this method as well.

FOLLOW THIS GUIDE AND YOU CAN GRAB - "Supreme Online Commander, "Ranker,
"Internet Commander," "Luditte," "Rushin' Front," & "To The Victor..." ACHIEVEMENTS AS WELL.
JUST MAKE SURE YOU CHANGE YOUR FACTION 3 TIMES!

I'm guessing since this title is now GwG (March 2016) - There is lot more people playing.
When following his solution, we teamed up about 50% of the time.
We came up with a solution to change our Location via Xbox Settings.

The same game plan applies - Find a boosting partner, go to Ranked under Xbox Live.
We noticed that (even changing location settings) if we didn't pick a certain game type, we were less likely to match up. So make sure you both pick the same game type.
When the game starts, the person giving wins simply quits the game.

FOR 360: Head to the "Settings" tab - Go under "Family" & make sure that setting is turned off. Next head under "System" - select "Console Settings" - select "Language and Location" & finally "Location" - This is where you pick the region you want to be in when matchmaking.
Now restart the 360 just to make sure the changes take effect.

For Xbox-One: Go to "Settings", Select "System", Select "Language & location."
Now select your new location from the list, and then select "Restart now!"
You must RESTART the Xbox-One.

The locations that worked best for us was: Singapore & South Africa (South Africa being a bit better). Although your free to chose which ever you feel might be less populated.

After changing these settings and attempting to match up again - We went from 50% match ups to about 85-90%!

Simply play on skirmish against an EASY AI with each of the three teams. To not even have to play, set it to a 4 player map, then select an EASY AI on the other team, and put the other 2 AI on "Cheating" and put them on your team. Sit back and watch the fun, then just rinse and repeat for the other two factions and you should have this in 10 mins