Before East draws, the table passes tiles in a fixed dance: three to the right, three across, three to the left. That is the Charleston.
Three passes
The first round is required: right, across, left, three tiles each time. The second round runs left, across, right, and any one player may stop it before the tiles move.
Courtesy comes after both rounds. You and the player across offer zero to three tiles; the smaller offer moves. If someone stops the second Charleston, courtesy usually still happens.
Jokers stay through all three. Flowers may pass. Chinese mahjong has no equivalent opening pass.
Practice the order in the Charleston lesson. Related: courtesy, East, joker.
Jokers never travel in the Charleston.