whistle

Whistling is a funny skill: folks who can whistle, wonder how anyone could have a problem with it. Folks who can't, wonder how anyone could ever produce such a sound. For those of you who can't, consider learning--a quick, loud, penetrating whistle has many useful applications and can be mastered with relative ease. (Note: there's nothing here on whistling Dixie or any other tuneful amusement.)

How to whistle loudly