I saw this picture and thought it was a great idea for mums wanting that reminder on which side boob is next for feeding time. Especially when 'baby brain' has really kicked in, haha. I find this is a lot safer than using a nappy pin.
It would be easy to make with a small length of ribbon and super gluing on two small magnets on each end. Then as you fold it over your bra, the magnets will attach.
I'm going to try this with bub number 3!