I was drinking 4 liters of water a day, and i really needed to go to the bathroom at nearly every class. I grew up in Montreal and High School ends grade 11. The problem was that I was a total fuck up in grade 8-10 and all the teachers knew this. When I would ask to go to the bathroom, it was to smoke a joint or a cigarette with my friends in the backyard. I would be gone for 40 minutes sometimes, and when I would come back to class, I would hold my stomach or make a disgusted face to give the impression that I had just taken a major dump.
One day in the 10th grade, I'm on a "bathroom" break, and I told the teacher that I needed to get some paper. After about 10mins, he shows up outside, and I have no where to go. He yells: "What are you doing!", and I say "I'm looking for some paper!".
What was my point again???... Oh, so grade 11, I clean up my act and I pick up BB. I needed to eat and piss several times a day, BUT I COUDN'T GO TO THE BATHROOM! My reputation had spread to every teacher. I couldn't take a fucking leak anymore.
So I used a prescription bottle, and made up the excuse that and I quote: (Looking very concerned and a little embarassed)"The doctors don't really know what it is Miss. They think It may be hereditary. I need to take these pills(show her the pills) or I will have kidney problems." I would sneak some food and eat it in the bathroom, and take a nice piss. This story can also justify all the water I was drinking in class.
I need to remind you that I am an expert actor(liar, whatever same thing), and there was no way a teacher was going to call my bluff. Be careful, French elite HS teacher will most likely not beleive you unless you performance is flawless. Just try to find something, and look embarassed and teary-eyed.
I beleive in you Blood, you can do it!!