So one day when one of the new Lts arrived I had a Master Sergeant take us up into T-tail of the C-17. the aircraft was having scheduled maintenance on it so we were lucky to have it inside a hanger well when we were sticking our heads out the top the Sergeant wanted to get someones attention on the ground just to make sure they didn't move any flight control surfaces while on top. He quickly did the wolf whistle with a screeching precision. I said to myself I am going to learn that. and about a month later I got it down good. Max always covers his hears when he sees me quickly making the okay sign and sticking it in my mouth.