Discipline means to lead or to guide. Leading or guiding a child with RAD is kind of like trying to lead or guide a wild untamed horse. It needs to be done gently and softly. Every see Horse Whisperer? Not a great movie to me but the message of gentlenss in training applies. We need to be child whisperers.
Consequences: Consequences in dealing with RAD can be ineffective. They have no cause and effect thinking. They can be sassy, mean and even aggressive and then ask pleasantly for a bowl of ice cream. I still believe consequences can be important because 1) if you have other children it would be unfair for them not too 2) in real life there are consequences, such: If you speed you get a ticket. If you don't do your job you may be fired. No one real cares if you "get it" or not. So they might as well find out there will be consequences. I very much believe in "Love and Logic" parenting. If you have not read the book by Foster Cline it is excellent for all children.
Punishment: I believe punishment is just vindictive and done to make the parent feel better. Don't punish. Discipline - lead or guide.
Beyond Consequences: I am no expert on it. I've read the book and watched the videos. I so appreciate the fact that they have the parent regulate themselves. Calm yourself before you discipline. Tell your child you need time. If they pursue you, as kids with RAD often do, when you are trying to isolate yourself let them know you are upset and they can have you talk to them and receive a consequence while you are angry or they can wait and give you time to think about it. Mine usually choose to wait. The only time this doesn't work is if the child is escalating and is losing physical control and there are other kids or pets around. Have the other kids leave the room and put the pets in another room and shut the door. Once you get yourself regulated then you can work on deescalating the child. Do not try to talk to them or consequence them while they are escalating. Wait awhile and talk to them quietly and gently. Let them know they are safe. You understand they are afraid. Be calm. BE CALM. oops sorry.