Tumblestone

Go to Multiplayer > Modifier of the Day > Press to bring up match settings > Select Tug of War as Gametype.
*You can reduce the win limit to 3 but I kept it at 5 to give me more time to wait for people to join.

Load up the game with 1 bot on beginner and just play through slowly, racking up a win or two and hopefully someone will join in the game. The bot is really bad so you shouldn't have to worry about losing anything. As long as the game ends with you as the winner and at least one other human player in the game, it'll pop your achievement!

You can invite players so you can invite a friend and play through with them and 1 or 2 bots and it'll unlock. You can invite them at the settings page when in the game lobby.