Panic

She trudged into Maths with conflicting emotions. She was bottomless, and had experienced a roller coaster of sexual pleasure during the morning, but she hadn't chosen any of it. This school was too much to take. And she'd been told to expect getting fucked in the ass by the big black teacher who's lesson she was now in.

Mr Footlong took the register. There were ten girls in the class, Erin was the only one she knew. 'Today's lesson is on probability,' said Mr Footlong. 'Poppy could you come up here please? To the front.'

She walked up to the front and stood by the board. Her anus was still aching from the **** at lunchtime, and her pussy was still wet. She really could do with cumming.

Mr Footlong got up from his desk and came to stand behind her. He stroked her ass with his hands from behind then he removed the buttplug, and stroked her bum hole. She instinctively opened her legs wider. He produced a big bag. 'In here there are one hundred marbles. 20 red, 40 blue, 40 green. Poppy - what is the probability of taking a red marble out.'

She was thinking of the answer when she felt his cock in between her legs. He was rubbing her pussy with it to distract her. 'Er....er.....20 over a hundred, that's er....one in five.'

'Well done,' he said, continuing to grind his cock against her pussy. 'Take a marble out.' It was red.

'What is the probability of taking another red one out?'

'19 out of a hundred?'

'Sorry, incorrect. Nineteen out of 99.' He lay Poppy down on his desk. 'I'm afraid you're going to have to answer the next question with my cock up your tiny ass.'

She gulped. The other girls in class came and crowded around the desk to watch. Her ass did pretty well with the first 3 or 4 inches - it hadn't properly recovered from lunch. 'What is the probability, if the bag is full, of taking three red marbles out in a row?' He was fucking her ass slowly now. She looked down and couldn't focus on anything apart from the big black cock sliding in and out of her ass. Mr Footlong motioned to Erin, who came and started playing with her clit. 'Er...one in five, then 19 in 99 then 18 in 99?'

'So close,' said Mr Footlong,' but I'm afraid that's not quite right. Let's see how much of my cock you can take up the ass for a new girl. The record is seven inches, by Olga. She can take nine now.' He withdrew long enough to pull his trousers and boxers right down, and several girls had their hands all over his legs, balls and cock. He shoved his cock back inside her rectum roughly. 'Have you got the tape measure Erin?' The cute ebony chick nodded.

Mt Footlong got a rhythm going, about a third of his cock pushing into her ass each time. Erin was still playing with her clit and she felt her orgasm building. Gradually the big black cock ploughed further into virgin territory, until Poppy screamed. The teacher stopped, and Erin measured. 'Six and a half Sir' she said. 'You are a good girl Poppy.' The next few minutes were a blur, as Mr Footlong expertly fucked her ass, gaping her sphincter and getting various girls to lick his cock, just as she thought she might be allowed to cum. Then, finally, he stayed inside her for more than thirty seconds and Erin went ballistic on her clit. Mr Footlong pushed two fingers up her pussy too. She shuddered and screamed out loud with utter joy and relief as a massive orgasm swept through her. Her pussy gripped the teachers fingers viciously, and her ass gripped his cock like a pair of pincers. Mr Footlong jerked, stopped fucking her, and came in her ass.

'That's how we deal with bottomless girls in my classroom,' said Mr Footlong. She greedily slurped on his cock, and giggled as the girls fought over who got to rim her asshole, which was dripping with cum. The rest of the lesson was uneventful. As the class trouped off to Physical Education, Erin whispered 'Make sure you're on my team, ok.' A minute or so later, Olga, the tall Russian girl whispered the same thing.