1) "Flebotinum" or as it's more commonly known "phlebotnum" has sort of turned in a medieval text (if you squint hard enough). But what is this term? Well according to Joss on his commentary for 'The Harvest', it came from David Greenwalt and essentially means "any magical or mystical force or event that arises in the process of inventing the Buffy mythology/or advancing the plot".
2) a word used by Lauryn that causes everyone around her to be confused about the fuck she's talking about. But only because she worships Joss Whedon, and they don't.
1) The phlebotinum in this episode of Buffy was verra sessy because it had to do with Spike.
2)Lauryn: You didn't see the new episode from Tuesday?! The phlebotinum was GENIUS!