An idiom meaning to make an already bad situation worse or to inflame a dispute; equivalent to 'add fuel to the fire'.
彼の一言がさらに火に油を注いだ。
His remark only added fuel to the fire.
議論中に相手を挑発するのは火に油を注ぐだけだ。
Provoking the other person during the discussion will only add fuel to the fire.
トラブルを起こした従業員を責めると、余計に火に油を注ぐことになる。
Blaming the employee who caused the problem will only make things worse.