The phrase "finger-snappingly with it" is a creative, informal way of saying that the term being discussed is very trendy or cool.
When someone snaps their fingers, it can be a gesture of approval, rhythm, or enthusiasm (like snapping along to music). So, if something is described as "finger-snappingly with it," it suggests it’s so modern, stylish, or relevant that it would make you want to snap your fingers in approval—essentially, it’s "in sync" with current trends or popular culture.
In other words, the buzzword is not just "with it" (cool or trendy), but so much so that it might inspire a positive reaction!