Julia Belluz writing for Vox:
Orbelo suggested the “straw technique” — strengthening your vocal cords by humming through a straw or blowing into one with a liquid (“like when you’re a kid and you blow bubbles in chocolate milk”).
Turns out, it seems everyone in the voice community knows about the magical straw technique — to “reset and free the voice” and “stretch and unpress” your vocal cords and folds.
The National Center for Speech and Voice says the method has “roots in Northern Europe and has been used for several hundred years.” Its popularizer, Ingo Titze — a vocal scientist and executive director of the center at the University of Utah in Salt Lake City — has published academic papers on the approach.
Apparently, the straw technique can not only give you a voice that’s stronger and more difficult to lose, but it can also relieve a tired voice.