Umm, what is boob punching?

Feministing posted this video of an apparent Internet trend call "boob punching." I'm always skeptical of any new Internet trend, especially if it doesn't include the words "cat" or "porn." But as we see in this (possibly NSFW) video, there apparently is some kind of yearlong history to videos of women getting punched in their boobs -- or, as the classy host of G4's "Attack of the Show" calls them, funbags. You know, men have been getting kicked in the junk for centuries in order to elicit a few cheap laughs. Nice to know that asinine comedy is gender neutral, folks.