A very intense exercise sesion with special bikes.

"Ahhh, what do you want us to do exactly ?", asked Andy.

"It's easy, all that you naked boys and girls have to do is to use these bikes", George said as he unveiled a bunch of these bikes from the storage room.

"Do they have something special or..", Hannah asked before getting interrumpted by him.

"You'll see, but for now, GET TO WORK YOU LAZY WORMS OR ELSE I'LL PUT YOU THROUGH HELL AND BEYOND!!", he yelled, upon which, everyone got in the bikes immediately.

"Good, now give me 50 laps to the field, or else", he demanded, upon which, we began working.

Even through at first these appeared to be normal bikes, as Olivia and the others were using it, they noticed an strange something about it, or rather, and strange sensation of vibration in their bottoms as they rode them.

"Heyy, isn't me, or i'm feeling something weird down there", Hannah said to Olivia as they rode the bikes.

"Yeah, me too, it feels like my ass is shaking constantly", Olivia replied.

"I wanna die!!", yelled Andy as he passed by.

"heh, i really did outshine myself this time", George said to himself as he watched the nude students ride the bikes.

"Ehh, sorry teacher, but may i ask something ?", a boy named Louie that had already finished his instructions said.

"Yes ?", replied George.

"Why are the nudies yelling something about the bikes ?", he asked.

"Ohhh, Louie, don't tell this to anybody, but these are special bikes", George said.

"And what's soo special in them", Louie asked.

"They have an malfuntion in their seats that maked them vibrate, and since those fools are naked, what better things to do than give them some pleasure and pain", he explained.

"Okay...", Louie simply replied.

40 minutes later.

"Alright class, see ya next time", George said as he let the students leave his class.

"Man, i'll rather break a bone than to deal with this again", Olivia said to Hannah while rubbing her own ass as they left the class.

"Yeah, i hope that the next class isn't soo bad", Hannah replied as she too rubbed her own ass. Upon which, the two went to their next class of the day, which was...