how do i not fall asleep in class

title; I'm lowkey pulling an all nighter to finish like 8 due assignments. I'm also fasting for Ramadan so no I can't drink cold water like I usually do to stay awake. My first 2 classes are unbearable because they are dark rooms with the most monotone teachers ever and iirc I have a loong test in one of them. How do I not literally crash into my desk? Thumbtacks?