This is on a Chinese site and I could not translate it and I don’t think it was a DIY. Pinterest user serenity 422 explained how to make it.  Take an old sweater. Cut a slit in along the shoulder down about 7″. Fold over raw edge and sew in place. Sew a piece of ribbon about 15″ long to one side of neckline and another ribbon to the other side of the neckline. Tie together!  Thanks so much for the directions serenity 422