Heee, fantastic! Such smooth writing, captivating writing. I giggled madly at the way you twisted and wove some of the canon moments into this. Percy's characterization is fantastic here; I love the way he tries to confront embarrassment with a matter-of-fact approach, and uncertainty and hurt with bravado.
Percy's voice is harsh, demanding. "I cast the spells on the way up. Get your clothes off and your cock up my arse, Wood."
He's such a bossy little shit. ;)
And the way Oliver figured it all out in the end -- marvelous! I was beginning to suspect he never would. :P Well done.