Go to Pro Tour and search the party mode playlist. It will cycle through the party game modes and the one you are looking for is Invasion. It's basically a big version of the smash attack events from single player. Cardboard aliens appear that you need to smash through to get points while avoiding the cardboard buildings. For this trophy, simply get through a round without hitting any buildings and getting negative points from it. You don't have to win or do well so can just sit in a corner if you like. The trophy will pop at the end of the round.