Calling a 21 “Meier” reverses the direction of play.
Flow: shake the cup, peek secretly, announce over voice chat (truth or lie) and pass on. The next player trusts (shakes), doubts (reveals) or tries to bust you (If your roll is lower than the previous).
On reveal: if the call was true, the doubter drinks. If it was a lie, the caller drinks. Whoever drinks starts the next round.
This game requires you and your friends to be in a voice chat.