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 in the round, throw a snowball at the other player's feet, so that they fall onto the second layer. Follow them down, and then do it again so they fall onto the third layer, and you follow them down there again. Once on the third layer, throw another snowball at their feet so they fall into lava. Once they die, the trophy should pop.