Vaping, or electronic cigarette smoking, is considered a more healthy substitute for smoking. Therefore, vaping in a dream can mean you want to substitute something that is bad in your life for something less harmful, while still retaining some of the joy.
Vaping is usually considered more socially acceptable than smoking a cigarette, so it could be that your vaping dream suggests you’d like your habits to be more acceptable to society.
As opposed to smoking, where a large quantity of toxic substance is inhaled, vaping involves a larger amount of non-toxic substance, in this case vapor, leaving your body. So with this in mind, the release of vapor in your dream through vaping can symbolize a cleansing of your body or mind.