I recommend Google searching "Dominican Blowout" for a more comprehensive answer.
But basically, it is a technique used to make the hair pin straight without the use of any chemicals. A paddle brush and a hair blow-dryer and very little hair product is all that is used. It sounds like a simple "blow drying the hair straight", but you will see that it really is not. It's all in the hands that perform the trick, there is a special *magic* along with the skill that produces a true "Dominican Blowout". The results are fresh, mobile, shiny hair that has a nice swing to it, and IMO it looks 1000% better than any hair relaxer I have seen, even on 4b hair types. I would highly urge you to look into getting one done if that type of service is available in your area. (*Hint*, they don't do it in black salons usually, mostly Hispanic salons.)