Any player may claim a just-discarded tile out of turn to complete a Pung, Kong, or Quint — but the claimed set must immediately be exposed on the table.
Calling lets you jump ahead in turn order to grab a tile you need, at the cost of revealing that set to everyone. After calling, you discard as normal and play resumes from your seat.
Example
If you're holding two 5 Bams and an opponent discards a third, you can call "Pung!" to claim it — but that Pung must now sit face-up on the table for the rest of the hand.
