The cherry blossom sprig thing. You get a consumable and then there's a memento. I stood by the crowd and used the one that was a memento, not the consumable and was able to get it. It did feel like it needed to be 20 different people though.
Its the consumable you get from the jester's quest
A side note, do it at a bank with a bunch of people in front of you, each toss can hit i think up to 12 people. I got mine done at the place you get the jester's festival quests in Auridon and only used 4 items.
Anyone in frontal cone gets hit. #protip
Tl;dr really weigh the fun you have in game vs the business practices you are supporting.