nibra:
Not an important topic
LIES AND SLANDER THERE IS NOTHING MORE IMPORTANT THAN BUBBLE BUTTS.

Anyway, bubble bottom/butt is a pretty common slang term in my experience. I suppose it could be a regional/generational thing. The woman you mention probably thinks of what she has as a "bubble butt" along with various other colloquialisms. "Ghetto booty" is another popular one, though it has some bizarre racial connotations.
Lochinvar:
I would imagine she'd call it her weapon of mass distraction
And if you had something to spank it with, that would be a weapon of ass destruction right?