When a girl with large breasts wears a small bra, thus her tits spill over the top of her bra. also known as muffin top of the breasts.
"Dude, Jess has some major tit spillage goin on"
"woaaaahhhhh..."
by ta boob expert July 8, 2009
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The section/area of a womans tit, that protrudes past the cup of her bra, which indicates that the tit has literally spilled from the bra cup as it is to large for the bra.

It's the bra equivalent of a muffin top
Man 1 Woah look at the tit spillage on her
Man 2 OMG those tits are way to big for that bra
by Heloby October 26, 2012
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