I have a go-to punishment for fighting. One my kids know well. One they have come to expect - so much so that they punish themselves. It's simple really; I actually got it from my mom.
Anytime the kids are arguing or fighting, they have to go to the couch and hold hands.
They say there until they make up. Sometimes it's 10 minutes, sometimes it's 10 seconds.
Yesterday the girls got into a big argument about something super important like trains. So I told them to go to the couch and hold hands and before I could walk over there and "take care of it", Radley stepped in...
Rad: I got it, Mom.
Rad: Emmy, what's wrong?
Emmy: sobbing and saying something.
Radley: So, what you are saying is that Landry hurt your feeling because she broke your bridge?
Radley: Ok... calm down.
Rad: Now, Landry. What's wrong?
Landry: sobbing and saying something
Rad: Now...you didn't want Emmy to put the bridge onto of your track?
Rad: (to Emmy) Can you build a track somewhere else?
Rad: (to Landry) Can you be nice and let Emmy build a bridge?
Rad: Ok. Now say you are sorry and hug.
Meanwhile, I'm eating bon bons and sipping on a white russian.