Since NPCs like https://subeta.net/users/[npc]%20wrapping%20elf can receive gifts, why not add some functionality to that? It could be a way to distribute gifts out to random people. Whenever they get a present, they'll send it back out to a random (active) user. Perhaps the source would be anonymous.
"The interesting hyperbolic structures on a pair of pants are easily classified" -Wikipedia, Pair of pants