To exchange blows; to hit each other (mutually striking one another).
居酒屋で客同士が言い争いになり、ついに殴り合いになった。
Customers at the izakaya got into an argument and finally started exchanging blows.
子どもたちが公園でけんかして殴り合っていたので先生が止めに入った。
The children were fighting and hitting each other in the park, so the teacher intervened to stop them.
試合中に両チームの選手が感情的になり、ベンチ前で殴り合う事態になった。
During the match, players from both teams became emotional and it escalated into a fight in front of the benches.