A fucking machine

At the back of the class, you see a big apparatus: a cushioned bench with leather straps to block wrists and ankles, and on both ends two massive dildos ready to spitroast the unlucky one strapped to this machine.

"To instill discipline in all of you, starting from now, we will have an exam every class and the person who scored the worst will be strapped to this discipline machine for the entire duration of the next class. I will now hand back the tests from last week and a first person will be disciplined."

She starts handing out the tests from best grade to worst and soon there is only two people left : you and Adam, another male student.