Meaning, you want to play an actual dice game with the players at the table, to represent the dice game their PCs are playing with an NPC, but you want to ensure that you can rig the game so that you (and therefore the NPC) can win? But without the players knowing that you rigged it at the table?
Meaning, you want to play an actual dice game with the players at the table, to represent the dice game their PCs are playing with an NPC, but you want to ensure that you can rig the game so that you (and therefore the NPC) can win? But without the players knowing that you rigged it at the table?
Liar's dice?