Lyric discussion by MrGrunge 

Cover art for The Whistler lyrics by White Buffalo, The

Another great song by The White Buffalo – Oh Darlin, What Have I Done has almost the same meaning.

So, this song's about evil spirits inside of you, that makes you a different person, a monster. You are trying so hard to keep it inside of you, but sometimes it doesn't work. Some thing happened and it blows your mind, you can't control yourself and do the shit that will make you regret for the rest of your life... Often such a crazy situations happens when you're in relations with girl, you probably love her, but can't stop doubting and settle down. Then you make huge mistakes...

Actually, "The Whistler" is murderer, character of the same named American radio mystery drama.