吞云吐雾

idiom

to swallow clouds and spit fog; (derogatory) to smoke opium or cigarettes heavily, blowing thick smoke

Originally derived from Taoist alchemical practices describing the breathing exercises of immortals, this idiom has shifted to a negative connotation. It is now used mockingly to criticize heavy smokers or opium addicts, implying self-indulgence and disregard for others. The parenthetical note in the source text explicitly marks this as carrying a mocking or derogatory tone.