This was a wonderful chapter, as is all of your writing. I loved how you set the beginning with humour--

He'd always known he'd do something special in life and now he'd discovered it was to be a champion producer of saliva.

Certainly he'd had worse ones and if a little sex was too much to ask out of life, then he wanted a refund.

--before you made us realise the horror of the situation, bringing us into the story gently, making us not expect the saliva to be blood so that it hits all the harder.

And this chapter deserves much more praise than I'm able to give it at the moment.

But I loved the ending as well, the way you brought in all the complications, and then they're forgotten while we start to become mesmerised by the description of Harry, by your ever-gorgeous and sensuous words, humour slipping back into the story as Ron says, "Even without glasses, he was fairly sure Harry would notice that," and then you bring all the complications back at the end, making the final moment bittersweet, especially since it's a complex sentence, the sex and the thoughts both independent clauses--the two are inextricably intertwined, making the ending very memorable, beautiful and sexual, yet sad.

Very well done. You rock

A few problems:

Misplaced modifer:

gold-handled knobs and delighting in the various soapy waters that poured out like a child.

General error:

if he'd been anywhere but it this school