Oh...my...God. He wants gum, or the magic secret gets it. Extortion is a federal crime, contact the FBI.
Well, obviously, the advise to "show the heckler up", that is so popular here in Penguintown, worked well here
. Maybe you should add the "punch the kid" advice to your routine and things will only get better.
Seriously, though, you really need to ignore this kid and not do magic with him around. If he continues to be a jerk, then the problem is not really a magic performance problem, as much as a "how do I deal with my peers in school" problem.
Wayno's advice to learn some different sleights is good, but it may require some patience and a willingness to do fewer effects until you know more. But you could learn some good controls from Royal Road to Card Magic, like the Hindu shuffle control and the overhand shuffle control, neither of which require a break. Also, if you do need to show this kid up, look to something simple such as a keycard trick, which combines some of the power of both the force and the control and, surprisingly, many semi-knowledgeable laypeople never suspect it.