Chapter 4

On the third week, they rolled another three. Not a three for him or for Sarah, but a three altogether. Thomas felt like crying. He could hardly believe it. Already, it had been three entire weeks since he had been locked up in chastity, and the only thing he was able to get was another dry and painful handjob without the slightest hint of relief.

His body couldn’t take it anymore. Being forced back into his chastity cage after that was like a blow to the soul. Every day he had to wait felt like an eternity of punishment, and the frustration wasn’t made any better by the exercises he had to do after school. Especially since he could hear his sister at the same time through the walls of her room, biting down on her pillow as she went through her own routine as well. God help them both if their mother ever got the idea of making them do it together. Get edged, wait a week, and then get edged again. Any more of this, and his brain was seriously going to melt.

As such, by the time the fourth week came around and he rolled a four, it was as if the heavens themselves had opened back up. A blowjob at the very least, with perhaps even the possibility of more. Sitting across from him at the kitchen table, Sarah scowled as she threw her dice into the bowl. Another four, making eight in total, and Thomas stared down in wonder at the results. He was dreaming, he had to be dreaming. There was no other explanation for what had just occurred.

His chastity cage pinched down hard against his member. He wasn’t dreaming. Sarah, however, was less than thrilled.

“That’s not fair,” she said, “You cheated!”

“What?” said Thomas, “How?”

“I don’t know,” said Sarah, “But you definitely cheated. You had to. I saw it.”

She stared at him hard, and he blinked back at her. Another moment passed as they sat there like that, him trying to remember what he did while she tried her best to strangle him through thought alone. Of course he cheated, which was exactly why she had brought up the point only after the dice had landed. Particularly when it also just so happened to be her roll.

Thomas felt a slight twinge of irritation. Twenty-eight days, that was how long he had to hold it in. An entire month of waiting, and it was only after all that time that he had finally managed to break through. Every time he went to sleep, he could feel his prostate shifting inside of him along with the weight of his balls. Just because her own climaxes were tied to his didn’t mean she was entitled to treat him like this as well. And besides, it wasn’t as if she got to cum anyways unless he did so first. If she really wanted a release, should she try to at least treat him a little better?

The thought was cut off in the next moment though as their mother stepped forward and waved for them both to stop.

“Now, now, your brother didn’t cheat,” she said, “He just got lucky. That’s all.”

“But we both rolled the same number,” said Sarah, “That’s like, impossible, right?”

“You both rolled a one two weeks ago, remember?” said their mother, “And it’s only a one in six chance either way, so it’s not like it’s that small.”

She looked over at them both, and Sarah frowned at the explanation. Thomas did so too. The math was simple enough, but it still didn’t make him feel any better about the results. For an entirely different reason of course.

Roll two dice, and the probability of coming up with the same pair was one in six. Something to do with the fact that the first roll could be anything it wanted to be, and the second die only had to match it. Given how long it had already been for him though, the numbers did seem just a little biased. Especially so when the slightest change in distribution made all the difference in determining whether or not he would be able to cum.

How many times had he seen a pair of ones before, the two black dots staring up at him as his member throbbed in his cage. Or a pair of twos, resulting in nothing more than just another edge that did nothing to relieve him of the pressure at all. And even when he had the gall to roll a three or higher, the other die always seemed to fall short, leaving him with another week of frustration and denial. Past that, any other combination might as well not exist for what it was worth.

Taking in a deep breath, he slowly let it out. At least today was different. Pussy, he was finally going to be allowed to put it in his sister’s pussy. Not another frustrating handjob or even her mouth, but her actual pussy. And judging by how backed up he already was, the moment he could feel her walls clamping down...

Idly, he watched as the rest of the conversation petered out. Sarah arguing one way, and their mother the other. It was the usual buildup that always seemed to happen every time they were gathered together. A few jabs here, a parry there, and then with one final threat of punishment, it was finally time for them to start. Standing up from his chair, Thomas reached down to take off his shirt. He forced himself not to hurry. His pants came off a moment later, and then his underwear as he stood there with his hands at his side and his chastity cage exposed. His heart beat slow and steady, like a ripple across a pond.

“You too, Sarah,” said their mother, “Don’t make me tell you twice.”

“And if I don’t?” said Sarah, still scowling.

“Then I’ll give him three extra points and let him do it up your butt,” said their mother.

She smiled in triumph even as Thomas felt his member twitch again down below. Well, there was no getting around that, as good as it would feel. For him and not for his sister, since doing it up the rear meant that her clit would be left completely ignored. An unsatisfying anal only orgasm for her, if she could even get one, with the climax being all but ruined in the sense that she would have to take it without so much as a finger to clamp down against inside her tunnel. Nothing but empty air, and the frustration of knowing that she would have to go to bed with a full load of his semen pumped up her rear hole.

As such, one last look of hesitation, and then Sarah began to take off her clothes, reaching down first for her shirt and then her bra. Already quite red, her face seemed to burn even brighter as the perked-up ends of her still growing breasts started to show. Thomas tried not to look too hard as she bent over to take off her panties and her skirt. The hard plastic sheath of his chastity cage was already tight enough as it was.

He closed his eyes, forcing himself to remain calm. One final breath from the both of them, and then standing there side by side as naked as the day they were born, they waited for the signal to start. Their mother walked forward with the key, and he gasped as his member sprang up. Already, just from the air brushing across the tip he felt like he was about to explode.

“Eager, aren’t we?” she said.

“N- ... no,” said Thomas.

A finger reached up to slide partway up his shaft, stopping just behind the edge of his glans, and he tried not to groan. After an entire four weeks of buildup, he would have done almost anything to be able to cum. Even if it meant a long and uncomfortable prostate milking, so long as he was able to let it all out. Once they got to around the two-month mark, even an electric massager up his butt seemed better than nothing at all.

Fortunately for now though, he had much better things to look forward to. A second stroke, and he bit down on his lips as their mother pulled out a chair for him to sit down. Sarah followed up to stand in front of him a moment later, and giving him one last look of indifference, she spread her legs to either side as she turned around. Dimly, he felt his eyes move over the soft indents left across her back by her bra.

“No grabbing, okay?” she said.

“R- ... right,” he said.

Well, this was it. The moment he had been waiting for. Thomas swallowed hard as Sarah placed her hands on her knees and bent forward. Like this, with her back arched up, he could almost see the outline of her pussy between her legs along with the entrance of her rear hole. A view that only grew all the more clearer as the timer beeped out at sixty seconds and she started to lower herself down.

Fifty-nine...

Fifty-eight...

Fifty-seven...

Their mother watched from the side. There was a long moment of silence in which Sarah seemed to hover less than an inch or so away, and then he jumped as he finally felt her pussy brush up against his member. It was happening, it was finally happening. Looking down, he watched in slow motion as the tip of his dick brushed up against her lips, pushing inward ever so slightly as it spread them apart. Soft, so soft, like a tongue swallowing him whole. He gasped, savoring the sensation he had been denied for so long. Just a little more, and then...

Unfortunately, whether it was the fate of the universe or something else, that was all he was able to get for now. Like most other of the other times before, where he had been cut off at the very last moment right he was able to cum. Thus, just as he could feel the softness of her labia sliding over his glans, he groaned as the slickness of her entrance caused it to slip back out. Sarah lifted her hips up to try again, and this time she winced as his member slipped upward to poke against the delicate covering of her hood.

“Ow,” she hissed, “Don’t hit me there. It hurts”

“Sorry,” gasped Thomas, “I didn’t mean to.”

Of course, just as he said that, his member just had to spring up again to tap against her clit once more. He grit his teeth, doing everything he could to keep himself still as Sarah glared back at him for the second time in a row. It was hard to remain calm though when he could feel the tip constantly rubbing up against the entrance of her tunnel. And when combined with the fact that neither of them were allowed to use their hands to direct themselves, even the simple act of trying to line it up seemed all but impossible.

Fifty-three...

Fifty-two...

Fifty-one...

A third tap, and Sarah let out a sigh as she missed once more. Her pussy slid down over the top of his shaft, and Thomas groaned as he felt the warmth radiating off of her skin along with the fluids of her own denial. Four weeks for him and four weeks for her. Already slick from their previous attempts, her pussy spasmed against him, and he resisted the urge to thrust. The longer they spent messing around like this, the less time he would have to actually cum. Not to mention the fact that every second they spent rubbing up against each other like this would only increase their frustration even more.

The fourth time around they were luckier though. As the tip of his glans pressed up against her opening one last time, he groaned as he finally felt himself sinking into the soft and warm depths of his sister’s tunnel. Leaning back against him to rest her head on his shoulders, she whimpered as she sank all the way down to the hilt.

“Oh, it’s finally in,” said their mother.

Standing up from her seat, she walked over to examine the connection, spreading their legs apart for a better view. Reaching out her hand, she ran her fingers over the place where the stiffness of his member disappeared into the softness of her folds. Sarah whined in protest, her breath coming in short gasps as the fingers moved up a moment later to trace a short circle around the edges of her hood.

“Look at that,” said their mother, “All snug and tight, almost like it’s just begging for a stroke. Now just imagine what it would be like if you hadn’t listened, and I had to make you do it with your backdoor.”

She smiled again, and this time it was Sarah’s turn to moan. Thomas felt her walls clamp down against him in response. Looking over her shoulder, he could almost see the swollen nub of her clit peeking out from the top of her lips below. Her hips shifted against his, and she let out another quiet whimper as she tried to bring herself back under control.

Besides them, the timer continued to count down. Forty-five seconds left and then forty-four.

Forty-three...

Forty-two...

Forty-one...

Just a little less than a third of the way through.