Literally the plural for more then one boob but derpy.
Usually used In a context of some real big honkers but can also be used casually with some average sized badonkers. It should also be yelled and never said without the derp
You know that sweat stain that ladies get under their boobs? The sweat pours down the central boob canal, and out the sides in the underboob regions - thus forming the sweatstain in the shape of a mustache... aka, the Boobstache.