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to steam (food, towel, etc.)
to be hot and humid; to be sultry
お母さんが肉まんを蒸しています。
Mom is steaming meat buns.
今日はとても蒸して寝苦しい。
It's so hot and humid today that sleeping is uncomfortable.
祖母が昔ながらの方法でおこわを蒸した。
My grandmother steamed glutinous rice the traditional way.