Nnnngh, I think you hit just about all of my bullet-proof kinks here. Young Snape, virgin Snape, fumbling teenage first time sex, a bit of dirty talk, wanking, nearly coming to soon... Yeah, that's pretty much all of them!
Severus smirked at the proof of his own instinctual brilliance, but simply said, "That will take some time."
After all, he'd have to do quite a lot of research in the Restricted Section first.
LMFAO at that!
Nice Snape voice too. Snarky and unfriendly and blunt -- real disdain as well as a cover for his insecurities.