Metagaming

Metagaming happens when a mun uses information gained in out of character conversations to influence in character interactions.

Examples:
 * You discover out of character that Pup A is a werewolf.  Your pup has no idea that his new friend is a werewolf, hasn't been told, and can't have deduced it through any other means, and yet they now wear wolf's bane or load their weapon with silver bullets.  You are now guilty of metagaming.
 * You have a conversation about Pup A's background out of character, and you discover that they're scared of ducks.  Without ever having mentioned the fact in character, or being able to deduce the phobia in any other fashion, your pup decides to unleash a horde of ducks on them. (Because, admittedly, that'd be funny.)  You are now guilty of metagaming.