SUP Magazine: How to Whistle With Your Fingers to Grab Anyone's Attention

If you don't know how to whistle with your fingers, you're in good company. The famed finger whistle is an old-school skill like making the  best paper airplane  that seems to mystify and elude each new generation. Learning how to whistle loud with your hands is no less impressive and useful now than when every '80s high school football coach was doing it.  Moreover, even though it might've seemed like an unattainably cool skill to have back then (reserved for only the most comma...