"...the loser becomes my sex for the rest of the school year?"

Rebecca pursed her lips in thought at the suggestion, but it wasn't long before she gave the only answer she could: "Yes, that sounds like a fair prize. What do you say, girls?"

"I don't know," Julie answered with a frown, "That sounds really ****."

"Not to mention probably illegal," Deborah chimed in.

"Let me worry about the legality of it," Mr. Dinger said with a dismissive wave, "As for it being '****', perhaps it is, but so is taking a Virginity Pledge. Wouldn't you all agree that if you back out of it at this point, you deserve to be a sex ****?"

Julie stroked her chin in thought, "Well, when you put it like that, yeah it does."

Deborah nods in agreement, "Makes sense. Besides, it's not like I'm going to be the one to cave. I've come too far and resisted too many cocks to give up now."

"We'll see about that," Rebecca said with a smile, "I just know that neither of you are going to outlast me."

"Well I won't be giving in!" Julie said confidently.

"Alright girls, enough trash talk. I think everyone gets the idea," Mr. Dinger said with a laugh, "Besides, there's only one way we'll know for sure. Are you three ready to go?"

The girls looked at each other, then turned to Mr. Dinger and nodded in unison.

"Then on your marks..." he said, undoing his belt. He popped the button of his pants and unzipped the fly, "Get set..."

He grabs the waistband of his pants and underwear, then yanks them down, revealing his rock-hard dick, "GO!"

All three girls locked their eyes on the penis, and their mouths started watering almost immediately. Mr. Dinger quickly noticed that each girl seemed to have a different method of dealing with the excess saliva. Julie tried to swallow her spit as much as possible, while Rebecca just let it pour out, occasionally wiping her mouth with her arm if there was too much build-up. Deborah meanwhile had a habit of licking her lips, possibly as a method to try spread the saliva around her mouth rather than have it run down her chin. The results were only somewhat successful, but it had the effect of making her look like she was starving for his dick, which Mr. Dinger found pretty hot. The one common thread between the three girls was the resolute look in their eyes, none of them wavering in the slightest.

Of course, Mr. Dinger couldn't let that stand.

"Magnificent, isn't it?" he said, temptation oozing out of his voice like honey.

"Yeah," Rebecca said, the other two girls nodding in approval.

"I don't mean to be egotistical," Dinger lied, "but is my dick the best one you three have seen so far? Be honest."

"Yeeeeesss," Jule cooed, looking entranced. A trail of drool manages to leak out of her mouth and drip down her chin before she slaps herself, "No! Snap out of it!"

"What's the matter Julie? Ready to give up?" Deborah teased. Her voice was confident, but the shaky way she kept gazing at the erect member in front of her and running her tongue along her lips told a different story.

"It does look juicy," Rebecca let out with a sigh, "But that doesn't mean I'll be sucking you off. magnificent or not, it's still a penis."

"It can't be easy to resist though," Mr. Dinger said, "After all, wouldn't be so easy to just give it a taste? You'll never know for sure otherwise."

"If I wanted the easy way out, I wouldn't have taken the Virginity Pledge," Rebecca replied, wiping her chin of the torrent of saliva that poured out of her mouth alongside her words, "B-But at this point, I wouldn't blame Deborah or Julie if they decided to give up now."

"Oh, I'm just getting started!" Deborah declared, "Unlike you two, I can keep this up all day."

"I'm stronger than one dick," Julie said, more to herself than the others, "Even one so big and... no, I'm stronger!"

Mr. Dinger's cock twitches at this point, his arousal at an all time high. This has a visible effect on all three girls, who start breathing heavily as their composure is shaken.

"Damn..." Deborah muttered, practically panting at this point, "I'm not giving up yet or anything, but... damn."

"I know what you mean," Rebecca agreed with a hushed whisper, "It's so..."

"Appetizing?" Mr. Dinger suggested. Instantly all three girls nodded, their determined looks from earlier now replaced almost entirely with awe and hunger. The teacher just smiled at the sight. He could tell it wouldn't be long now before one of them caved.

To their credit, they ended up lasting longer than he thought they would, given how heavily he rigged things in his favor. There was a long period where they were all silent, save for the girl's labored breathing and the occasional smacking of lips. Eventually though, the moment Mr. Dinger was waiting for finally happened.

"Aaauugh, I give up!" one of the girls exclaimed, dropping to her knees in front of him, "I can't take it anymore! I have to know what I'm missing!"

And with that, Mr. Dinger felt a warm, soft mouth envelop his cock and start vigorously sucking him off.