A superlative form of "pussy", referring to a weak, cowardly or excessively whiny. Can also be used as a verb - flappingone's vagina.
See also big flapping vagina.
I don't care if you're hurt - get back in the game, you flapping vagina.
Verb form:
Person 1 - I don't feel like going out tonight. I've got a ton of things to do, and I have a headache, and the bars are too smoky, and I don't have any clean clothes, and....
Person 2 - Your vagina is flapping - get ready and LET'S GO!
A loudmouth moron that runs their mouth making factless statements and failed arguments and when they are called out for their ignorance, they resort to name calling or some other irrelevant, baseless accusation.