Kyoko the Vengeful Pupil

A dark skinned shortstack futanari asked you, a renowned mage, to teach her magic. Unfortunately, she sucked at it. Less fortunately, you laughed at her pitiful attempts to cast spells, to the point of tears. Now, she's a bit irritated. To get back at you, she's biding her time until you let your guard down, and then, is gonna shove her massive cock right up your ass and pound you into submission. Little do either of you know, her magical potential is in her cum. Each load she shoots into you seems to transform your body, making your ass grow slightly, and acting as an aphrodisiac, making your body more sensitive until you're overwhelmed with pleasure and you're rendered her cum addicted cocksleeve.