Erica flicked her tongue at him in irritation, slithering up Derek's arm to rest her head on his shoulder. Derek rolled his eyes. "You're something, alright," he said, pulling out his wand and murmuring a warming incantation over the blood, taking out the cork and testing a few drops on the inside of his wrist before giving the bottle to Stiles. He held his wrist up to Talia for a snack. "No biting, little one," he said. "I know it smells good but we taste with our tongues, not with our teeth."