I tried for years to whistle with my fingers. I’d drive around, basically spitting on my hand, down my arm, with nary a toot.
One day I was on vacation with a friend in New Orleans, and we got separated. I could see her, but she couldn’t hear me from two blocks down the street. I stuck my fingers in my mouth as I’d been instructed by many finger-whistling friends in the past, and blew.
I got the perfect New York taxi driver whistle, Stephanie turned around, we were reunited and all was well.
For a few years after that, I could only get the whistle when I needed it- lost a friend in a crowd, needed a taxi in NY (that was satisfying), etc. Now though, I can muster the whistle when I need it, and I love it.