Looks like you don't have a lot of choice

"I'm not really sure I should..." you began to explain

"Please, Mr. Doe! This is our final grade for the semester! If we don't have a suitable model then we'll all very likely fail. It'd look horrible for the department and the headmistress would furious!"

Fuck, she was right, wasn't she. An entire class of thirty or more girls all failing their final projects would look horrible, ESPECIALLY on you even if you were just a substitute. It seemed like the only option was to act as model for a little while even if it did make you more than just a little uncomfortable.

Swallowing heavily you made your way to the front of the class, nervously pulling down your tie enough so that you could simply pull it over your head. You could hear a small number of giggles around the room as you started to unbutton your shirt. This was for art, right? Art wasn't vulgar. It certainly wasn't porn. There were nude models that did this sort of thing all the time. No need to be ashamed about it. Of course most models didn't have the eyes of a few dozen senior girls running over them.

The giggles and whispers seemed to get louder as your shirt pulled off and set gently on the floor just behind you. Now your pants. Oh god... your fingers were shaking just a little with embarrassment as you worked your belt free, followed by your button, and then working down your zipper. The mutterings weren't quite as loud now as each girl seemed to be leaning closer to get a good look. Your cheeks were absolutely on fire as you started to work your pants off, boxers and all. Just do this and be over with it. You just need to stand here for the class and it'll all be done. Working off your shoes and socks while you pulled your pants down off of your ankles, you set the collected pile of clothes aside and took a deep breath. Ok, here goes. You stood up tall and straight for the class, a body entirely nude for them to see.

"Oooo..." came a few hushed voices around the class. Thirty four eyes were running over every inch of bare skin you had on display. You were more than a little certain that most had their gaze directed straight to your dick. Your swallowed nervously for a moment as you put your hands on your hips and stood in a way that you hoped projected confidence. A few students had already begun to work on their sketch books, capturing your likeness for their reference. Most were still staring. From the corner of your eye you caught a handful licking their lips.

Suddenly there was a tiny gasp, followed by another run of giggles, and the few students that had been sketching quickly ripped out of the paper they working on and began to rapidly work on a new sketch.

"Mr. Doe..." came Sarah's voice from the front row, a sort of mischievous tone in her voice. "You're getting hard."

Oh shit! You looked down quickly and sure enough your manhood was rising eagerly to be a model on its own. Your first instinct was to cover yourself with both hands and begin to reach for some clothes but a handful of voices rang out in quick protest.

"No don't!" said Sarah, the apparent spokesperson for the class. "We need to see the entirety of a males form. This is perfect!" You couldn't sure, but you could have sworn you saw her tongue run over her lips quickly after she said that.

Reluctantly you lowered your hands and let your arousal be taken in by anyone with eyes. Seven and a half inches of your meaty tool was on show and it was a free ticket for each girl in the class. You saw a few rub their hips together as some girls tried to focus on their sketching. In the front row you saw Sarah whispering to a few girls close to her. Occasionally one would glance in your direction, turn back to the group and whisper excitedly. Eventually the small huddle broke up and after a moment more one girl next to Sarah shyly raised her hand.

"Erm... Mr. Doe..." she said with a dark shade of red filling her cheeks. "Could we ask you a favor?"