What event was Lolita's custom action on?

As the title says. I've gotten every single cosmetic that Lolita has to offer, yes that includes her two emotes. I've even bought my very first starlight because Lolita's painted skin was there. But for the life of me, i couldn't figure out what event this custom action was. It really bugs me because this is the only cosmetic that is missing for my Lolita shrine. I just want to know what event this was on and repent for my sins 😭😭