Do not brush the hair back with a brush or comb. Instead, use only your fingers to pull the hair back. When securing the hair tie, do not completely pull the hair through before twisting and referring the hair through. Continue to do this until you have no more hair tie left. and voila! Messy bun in full effect!!!

@RubyDenise has it right and if it's too bumpy for you after you pull it up, just run a comb through loosely and it will still give you that laid-back look, but not sloppy.

Use your hands to scoop up your hair, not a brush. then twist your hair into a bun and secure it with the hair tie. Let the pieces fall naturally.

First try just throwing it up into a bun and take out some of the hairs so they fall out of the bun.

how i do a messy bun is get the elastic ready in one hand, then in the other take my hair and clump it into a ball then just wrap the elastic around it. sometimes bobby pins are needed to help secure it.

I like to do a low pony tail and pill it half through pull into a bun and allow the ends of the ponytail to be out. Then you can grab at the ends and pin, braid crimp them then tuck it back into the hair or flare out too,