To be honest, 'steeping' is a word that has been adopted by the vaping community, for years; but is technically incorrect. What we are doing with some liquids, particularly tobacco flavors, is 'aging', not steeping. Steeping more accurately refers to extracting flavors from a solid, by soaking in water, or some other liquid, usually warm. Making tea is an example of steeping.
Never the less, some e liquids require time, between the time they are mixed, and the time they are vaped, for the flavors to meld together. There are those who use various methods to try and speed up the time: Vigorous shaking every day, leaving the cap off for periods of time, putting the bottle in a pot of warm water, using ultrasonic cleaners, etc.
My experience has been, there's no substitute for time.