The fight should take place on gymnastics mats or another soft floor (sand, grass, etc.)
Two teams are standing on the fighting area, facing each other. The players of each team hold their neighbours (by putting their hands on their neighbours shoulders) so that the geam forms one massive object.
The objective of the fight is to move the other team out of the playing/fighting field. Only pushing (with the chest or the shoulder) is allowed, but not using the hands, kicking with the feet or the head, etc.