You finish the exam

Somehow, the lewd thoughts don't pull you too far away from the exam for the remaining time. You avoid shifting your hips, you keep the thoughts of submission and desperation at bay, and manage to write several more answers. There's no telling how good they are, but hopefully it will be enough for a passing grade.

Soon enough, the teacher calls out "That's time! I hope you all feel confident in your answers. Please bring your papers up to the front and hand them in. You should hear back about your grades within a week or so." Around you, chairs scrape against the floor as any remaining students stand up and head up to the front. Looking down, you notice a distinct dark patch on your jeans, and wait until most of the others have walked past you before heading up to the front. Your legs almost give out as you stand up, and shakily head to the front desk.