A gaping vagina is usually a girl who's
attention whoring so much that she's trying to suck everyone in her
sphere of influence into
fawning on her. Usually, she trades some sort of favors (likely sexual in nature) for something she wants from them, be it money, attention, affection or gifts.
Bob: "
That chick Mariboo was playing different guys for
money and
presents."
John: "Yeah, she's a gaping vagina."