Apollo's Philter--help?

[heartswill.livejournal.com]

Do you remember that old Potions book I showed you on the train? There was an original potion in there called "Apollo's Philter", which protects against poisons, infections, and illnesses for the space of a year. I think I was able to make it, and I've left it in the Chamber of Snogs. But I can't figure out how to get some to everyone. I think I have enough for everyone in the castle, and maybe some extra as well (just a taste is enough for it to take effect). Does anyone have any ideas?