The semi-horizontal space created by the top-side of boobs; depth and slope determined by cup size and perkiness.
NOT Boob Shelf.
"When she eats chips, she gets a lot of crumbs on her boob shelf", or "When I sit in my recliner, my kitten likes to nap on my boob shelf."
The bulge of fat/skin that protrudes atop and hangs over, the waistband on a woman wearing mom jeans. Similar to a muffin top, only approx 3 inches higher. Just below the boobs, creating a shelf for the boobs to rest upon.
Wow, look at the muffin top on that girl!! No, that isn't a muffin top, Tori, its a boob shelf. She is wearing mom jeans after all!!!!!!