You'd have to stop being an angel. I don't think you can. [It's not a judgment- in fact, Castiel remaining one of the few angels who can honestly say they're still pretty angelic is a feat.]

Oh, I know he's all talk. Maybe he'll do something a little dangerous, but once Rei and the cheerleaders or Mami and the Girl Scouts or any of the other little superhero squads get their claws in him, the fight'll go right out of him.