Ah yes, who doesn't like the Under Boob? But is it better than cleavage? We'll have to start this debate like any good high school argument would, with a definition. The Urban Dictionary has this to say about "Under Boob" :
Under boob is achieved by wearing a very short halter top or cropped tank, also known as an under boob shirt, which exposes the bottom areas of a woman's breasts.
It goes on to explain what makes under boobs so great is that they "can be enjoyed in any public venue", much like cleavage. Now, many men will argue that an under boob is better than cleavage, or even a side boob. We're not ready to declare our opinion on which is the best view of a woman's breasts, as we respect the breast in all of its forms, but these photos are certain to make a compelling argument!