Story search.

[Zbreaker]

I'm looking for a story. I was detailed but I may not be. I can only remember a few parts. The first part had a guy in an art class posing nude. He got turned on and the class giggled, having the teacher come onto stage and knee him in the balls to have hes erection subside. But the pain was what I remembered. Then one of the girls and a friend were doing science experiments for a "study" and put his balls in a cage through a small hole. They told him it had hungry weasels in it. He freaked and yanked out fast and the girls laughed and relieved that it was a hamster. those were the outstanding point of the story. I don't remember the title or where I found it in the first place. Please help. . .