This achievement requires you to complete a game where all in-game players guess at least one answer.
Open up two tabs in Google Chrome using the following method:
Click on the person image in the very top right of your browser. Go all the way down to "manage people" and click on it, then click on "add person" in the bottom right corner. Once you click it, click an image for them then click "save" in the bottom right corner. This will open a new pop up window for that person.
Join the game lobby with both tabs and start the game. Pick your passwords and sentences. Once the game starts, immediately guess the correct answer with the tab that is able to guess, then do the same for the second question in round one with the other tab. Repeat this process again in round 2, and you'll unlock the achievement when the game announces the winner.