Quick answer: The player who draws a 6 starts the group challenge agreed before the game.
What Does 6 Mean in King's Cup?
Six varies more than most cards. Choose the meaning before play so the turn stays quick. A short impression, trivia prompt, or group action works well.
Common 6 House Rule
A traditional version uses a gender-based group rule. A universal challenge avoids excluding or misidentifying players.
House rules differ by group. Confirm the meaning before the first card is drawn, allow anyone to choose a non-alcoholic alternative, and never pressure a player to participate.