So I'm joining a PBP game and one of the character ideas I'm toying with is a changeling (elf) bodyguard. I had this idea for a stunt called either "nooooo" or "get down" with which the character can replace another character in the same zones defense roll with his own, the idea being that he's pushing them out of the way or parrying a blow for them. Is this balanced? And does anyone have ideas for other stunts that fit the concept?