An extraordinarily large pair of breasts. So much so, that they have ascended beyond the point of simply being a "rack", and have in fact raised to the level of a "
shelving unit."
Often used as a way of expressing the sheer monstrous volume of fat contained within the
Mammory Glands of a
Homosapien (Human) Female.
Guy #1: Man, check out the
shelving unit on that!
Guy #2: I bet you could even rest your
elbows on them to light your smoke.
Guy #1:
My dream girl.