1. Mark the spot where you need an extra button.
2. Sew a new buttonhole on the same side of the placket as the existing buttons.
3. Sew a new button on the opposite side of the placket, where the buttonholes are placed – attach it on the inside of the placket.
Once finished, the extra button and buttonhole will be invisible from the outside, but they’ll keep your shirt lying flat at the bust.
