In recent years the brushing order has changed from COI to ICO. The new order is based on the loss of focus during brushing. While we are completely focussed when we start we might loose focus over time. The insides have a complicated technique from the beginning and are prone to cavities, so they are brushed first. The Chewing surfaces, are quite easy to reach and are simply brush, but also have very often cavities. Last we do the outsides, that are the most comfortable to reach/brush and have rarely cavities, so they are done last.
The technique is basically the same as for COI. On the insides we start with red-to-white brushing, on the chewing surfaces we simply brush and the outsides go through the stages of simple brushing, circular brushing, red-to-white and then finally together with the insides the Bass technique. The progress is based on the kids motor skills.