ALSO: What is that little ball on the end of an unpicker for?
With the zig-zag side down (towards the scalp) it helps the bobby pin slide into the hair. Not only is it easier, but it also holds the hair better.
The zig-zag of the bobby pin is designed to ‘grip’ onto the hair underneath while the straight part of the pin holds the hair in place neatly.
Knot Me Pretty on YouTube have put together a fabulous video on how to pull together different styles with using the versatile pins.