Cleavage for boys is all the rage.
Since men don't really have breasts (usually), how can you tell if it's heavage? One open button: casual; two buttons: heavage.
Editorial note: Whoa! You've found a super-old post here on BuzzFeed, from an earlier era of the site. It doesn't really represent where we are anymore, and may in fact be totally broken, but we're leaving it up as a part of our early history.