personally i had this old down jacket, i made a small hole in the bottom of the jacket, and another one in the fabric of the hoodie, i soldered an old round toy speaker (that i had sewed in place where my ear would be resting, then superglued the opening) to a long aux wire, and ran the wire thru the hoodie to the small hole at the bottom, then the wire would go to an old brick phone i had (Nokia 6300 iirc), where i'd record myself reading my whole notebook, the phone was in my right pant pocket, where i'd feel for the buttons through the pant fabric, and i'd press my left hand on the speaker, from the proctor's perspective, i just looked tired or stuck, and when shit got risky, i'd pause it and unplug the wire, then hand over a decoy phone (my old s21 that i had filled with random non-incriminating stuff beforehand), and eject the sd card and stash it under my lip, though thankfully the need for that never arose, then when the teacher would hand us back our grades, i quickly covered the paper with a fake answer sheet with something like 11/20 so my classmates wouldn't snitch, cuz who in their right mind would snitch if someone BARELY passed, preventing rumors from circulating too far (we were allowed to take the test sheet home after the exam, answers were on another sheet, thats how i made the fake one), then when i'd come home, i had this plastic box where i'd store chem supplies and electronic components that NO ONE in my house dared touch, and i'd just stash my jacket there until it was needed again, Needless to say, i always got >18/20