bird's eye boob
when you are walking on a higher level than a girl (eg; when she is sitting down or you look out from a freeway overpass) and she is wearing a dress and you can see her naked boobs from your angle.
"Hey! Check it out! Look at that chick below the bridge!"
"Wow! We've got a bird's eye boob!"
"Wow! We've got a bird's eye boob!"