Don't. Just, don't. I mean, who even cares anymore? If you're any good at IB anyway, you've already been accepted to the university of your choice. You already have your high school diploma. All of this is extra. So, don't do anything for the entirety of April and May. Just sit back and laugh at your friends, yelling "you suckas!"
Drink. Drink and eat. A lot. All the time. You know that environment saying thing "Eat food. Not too much. Mostly plants". Well, during IB exams it should be changed to "Eat food. Way too much. Mostly sugar". Because how else are you going to stay up late every night to study? And how else will you get up in the morning? Candy bars, chocolate, crazy energy drinks. Eat. Drink. SUGAR.
Forget it. Just repeat this to yourself multiple times a day. If anyone asks you to do something. Or if you want to to do something. Just say "forget it". Because you will have to forget everything. Everything you are, everything you want, everyone you love. Forget everything but studying. Then go kill yourself.
Go outside. While studying for these exams, it is quite possible you will have no need to leave your house for many days, unless you run out of graph paper or something equally as tragic. You will get to the point where you look up from your notes and see sun through the window and your eyes hurt, and only then do remember there is a life beyond studying. To stay sane, go outside. Go outside and dance in the streets. Run, as fast as you can, like a spazzy little kid. Run til your muscles ache. Your mind is exhausted. Let your body work out for a little while.
Find yourself. Ha, no, you don't have time to find yourself. But you do have time to find what will make you feel like yourself. When you are at the end of a long study day, identify what needs you have--do you have to go to the bathroom? Are you hungry? Are you tired? Do you need a mental break? Deal with these needs one at a time, as fast as possible. And then get back to studying.
Watch TV. You need a study break. Your break is only half and hour long, which means that you can't go anywhere and you can't really do anything. This is what TV was made for. Comedies are only half an hour long! Watch some reruns, internet TV, youtube videos, whatever. You'll let your brain rest, ready to get back to work. Plus, you won't miss any of your favourite shows during sweeps!
And then go jump off a building.
I mean, do you have a better solution?