This Trophy can be obtained at any point in the game during online play.
Whenever you see a fellow player making their journey, you can press the Start Button to sit down and begin meditating. In order for the Trophy to unlock you need to be sat meditating next to another player whilst they are doing the same.
Due to the lack of communication in game, you're going to have to leave this up to luck. Hopefully a player will see you meditating next to them and understand.
Whenever you see a faint white light around the edges of your screen the game is indicating to you that there is a fellow player making their journey. Keep at it and with luck you'll eventually find someone to meditate with.