Haha, very cute and fun! Clueless!Harry is also a Jealous!Harry, and Snape knows how to play him. Er, them. Which, hmmm, may include Lucius too.
More seriously, I love how we finally see why Snape puts up with Harry being so uncultured and petulant - which is enough to annoy anyone - in the scene in the workshop, when Snape's deep insecurity comes out. It's a weird relationship: Snape makes Harry jealous, to get Harry to show how much he loves him, which Snape won't ordinarily allow, because he doesn't want to seem dependent. LOL, they both need a shrink! But amazingly, it works. For this odd yet perfect pairing, this fic is a perfect demonstration why.