How to preserve a flat twist out

I did a flat twist out on my hair and i really like it. last night i put my hair back in into larger flat twist outs to keep the the style. the thing is, i dont want to have to do that every single night until i wash my hair again. does anyone have any suggestions on how to preserve my flat twist out. i would do a pineapple like i usually do but the back part of my hair tends to flatten out straight its really hard to make that little part like the rest of my head.