Sea Change (слэш)

'This wouldn't have happened if you'd just done what you were told for once!'
Merlin let out a tiny sigh, as if he was being tiresome. Of course, it wasn't the first time they'd had this particular argument but Arthur hadn't won it yet, so he had no choice but to keep trying.
'I'm the prince; you're my servant. I give orders and you follow them. That's how it works.'
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Five times Merlin did as he was told, and one time Arthur obeyed instead.
(Based on "Recalcitrant" for JAL)