Merlin Flashfiction - Accept no Substitutes by lamardeuse (Make Them Do It)
http://community.livejournal.com/merlin_flashfic/24279.html

In which Merlin is kind of an idiot, Arthur is hot, there is no such thing as a love potion, and everything works out for the best. (the usual then, but with porn)

It was extraordinary, Merlin reflected as he pounded down the corridor toward the Great Hall, how often the destiny the Great Dragon constantly spoke of entailed saving Arthur from beautiful women.

When a visiting noblewoman tries to charm Arthur with a love potion, it's Merlin's duty to save him. No ulterior motives whatsoever. :D

Merlin has to protect Arthur from a love potion. Sweet!

Merlin has to save Arthur from the clutches of yet another not-so-distressed damsel, who has gotten her hands on a love potion.

Love potions generally only had strength through the night, their power dissipating with the dawn's light. If Arthur could sleep undisturbed until morning, he would never know he had been enchanted, and no harm would have been done.

Love potion made them do it.