You decide to try your skills out on Cindy, a girl who was friendly to your face, but trash talked you behind your back. You sneak into the bathroom during home room, and set up a magical "Camera" of sorts. You start your magic on her, transferring her large breasts to yours.
As the class starts, she has to readjust her bra, but nothing noticeable. You feel your own breast start to enlarge slightly. 20 minutes into the class, and her boobs are noticeably smaller then they were at the start, while yours have started to lift your shirt high enough to see your stomach. As the class ends, Cindy is near flat-chested, and sprints to another bathroom to see the damage, as she screams, you turn your intentions to another girl who has scorned you....