add fuel to the fire
Also, add fuel to the flames. Worsen an already bad situation, as by increasing anger, hostility, or passion, as in Bill was upset, and your making fun of his mishap just added fuel to the fire. This metaphor dates from Roman timesLivy used it in his history of Romeand it remains in common use. For similar metaphors, see add insult to injury; fan the flames.
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