Whistling is weird.
I don't think about the notes I'm trying to hit.
I just think the song and make the song and my mouth seems to just know how to do it.
Sure, sometimes the notes aren't quite right, or a little wheezy, but the song is there.
There's no humming.
There's no singing.
I just think the song and I whistle the song.
And the song is real.
I'm sure there's a scientific explanation.
But it's also magic.