A common enough Christmas tradition in the UK (and I imagine elsewhere) - in the past anyway, even centuries ago - is to form a group, go and knock at some local randomer’s door, and sing at them. They might even give you a treat or a charitable donation for taking the time to do so, or possibly to encourage you to leave.
Anyway, this is the practice of door-to-door carolling, or ‘wassailing’ if you want to feel like an ancient Nordic.
Annie is right when noting that this feels extremely weird in modern times.
It’s a wild tradition when you think about it. You show up at strangers' homes and… sing at them. They stand awkwardly in the doorway, forced to listen to a few rounds of Gloooooo-ooooo-ooooo-rias before you yell Merry Christmas and release them to the blessed peace of their own home
Possibly almost inconceivably so to the new generation it would seem.
I just described this caroling tradition to my oldest two kids, who are sitting at the table crocheting, playing with Play-Doh, and watching Instagram Reels. They agree: Absolutely unhinged move. Showing up at someone’s house, stranger or friend, to stand on their doorstep and sing a traditional holiday anthem at them.
Although I suppose it could be rebranded as some type of ‘grammable flashmob and at least it might feel a bit more normal. To millennials at least, I’m too old to know whether flashmobs are also old and passé to the newest generation du jour.