The idea behind it was to help curl hair that didn't really coil at the ends and also to help hair that was really curly to keep from tangling at the ends so much. What you were to do was coil around the last one or two inches of your hair on the ends of a bobby (or regular hair) pin and then pin the twist across your head to keep your twists stretched or (if your hair was long enough), you could pin the ends at the roots of the twist to keep them secure. In effect, your ends would set in a curl pattern and would also be protected throughout the night such as sleeping rough enough so that your bonnet slides off in the middle of your beauty sleep lol.
I used to do this a lot back then, especially back then because I wasn't moisturizing my hair properly, so my ends were always dry and I always had to manipulate them some type of way to get a decent curl at the ends.
I know my writing it did not explain it entirely, so I created a sample video to show you all what I mean. I couldn't really find a video that could show you what I meant, so I made it myself lol. Hope you enjoy!
But until next time,
♥ Keep calm 'n coily ♥