Keeping kayfabe alive
The phrase is used to define that a pro-wrestler's respective character / identity / gimmick should be kept intact, whether they're inside or outside the ring. Pro-wrestlers are to stay in character during a match, or while inside the arena, with or without the cameras rolling, to make it look real.
Orange Cassidy posed in photos like he's still in his in-ring character, during a private event. He's keeping kayfabe alive.