Rules glossary
↑ Parent rule: 723.5 While controlling another player, a player makes all choices…
723.5a The controller of another player can use only that player’s resources (cards, mana, and so on) to pay costs for that player. Example: If the controller of a player decides that the controlled player will cast a spell with an additional cost of discarding cards, the cards are discarded from the controlled player’s hand.
No sub-rules.