What you describe is how it happens to everyone: magic does slide through you, and disappear, and come back later looking like something else. And I'm sorry to tell you this, but where your magic lives will always be a great dark space with scraps you fumble for. You must learn to sniff them out in the dark.
Robin McKinleythe touch of evil poisons by the idea of it. Reject the idea, and you've rejected the evil
Robin McKinleyShe laughed at him then, because he sounded like a small boy, not like a very large grown-up Beast with a voice so deep it made the hair on the back of your neck stir when you heard it. 'But vegetables are good for you,' she said, and added caressingly, 'They make you grow up big and strong.' He smiled, showing a great many teeth. 'You see why I wish to eat no more vegetables.
Robin McKinleyI like to assume that since I drive a car and maintain a respectable credit rating and rarely murder anyone and bury them in the back garden unless they really deserve it, that the fact that I hear voices wont unduly disturb anyone.
Robin McKinleyWhen they finished laughing they were on their way to being not just friends, but the dearest of friends, the sort of friends whose lives are shaped by the friendship.
Robin McKinleyShe poured the water, arranged some bread near enough the embers to scorch but not catch fire, and looked up at Little John. She was so accustomed to his step, to his bulk, that it took a moment to notice his face; and when she did . . . It was, she thought, rather like the moment it took to realize one had cut one's finger as one stared dumbly at the first drop of blood on the knife-blade. You know it is going to hurt quite a lot in a minute.
Robin McKinley