I'd recommend doing the "fake" multiplayer glitch for this trophy, which you can find how to do here: https://pastebin.com/Jgf6vPeJ
Before starting the round, make sure you vote for the Snowball version of Tumble in the vote menu. Alternatively, when you're creating the round, go into the Settings and set the game type to Snowball only.
Once the round starts, simply throw yourself into lava on the first and second rounds. Once on the third round, switch over to the "fake" player two and have themselves thrown into lava for the next three rounds. Once the game finishes, the trophy will pop. You will also unlock the S-No Throw trophy if you haven't got it already.