I learned how to do this using a needle and thread on a bias-cut fabric strip years ago from Roberta Carr. The most important details: stretching the bias as you stitch and being sure to start with a wider 'cone' at the beginning of the stitching.
The picture of the flower finished off with skinny tube comes from Roberta's book: Couture: the Art of Fine Sewing...a GREAT book you can find at this link: https://www.amazon.com/Couture-Sewing-Roberta-C-Carr/dp/0935278281