After lunch, Alan played tennis at the high school courts with his friend Peter. Then he went home and took a nap, after which he did some homework.
Life seemed surprisingly normal. Suzanne wasn't around, and Susan seemed content to go back to her usual non-sexual mothering role, at least for a while. It helped that she was sexually sated from her latest "breast self-examination."
In the late afternoon, he decided to go swimming in the backyard swimming pool. He did that often, though sometimes he swam in the nearby ocean.
Katherine was already sitting by the pool. She had just been swimming laps and was drying her hair in the sun. She swam in the pool a lot to keep in shape, but also, unlike Susan and Suzanne, she liked to work on her tan.
Seeing Alan coming, she stood up to say hello. "How are things, Big Brother?" she said jovially, while putting on a hair band.
"Things are very good, Sis. Very, very, outstandingly good," he replied. His mind had been focused on Susan and Suzanne lately, but his sister had also been on his mind. She was dressing provocatively and acting sexily, especially given her cheerleading display of a few nights earlier. It didn't occur to him that she might have realized that he had watched her practice her cheerleading routine in the nude, and neither of them mentioned the incident.
"I can't possibly imagine why things are so good," she told him, smiling all the while. "It can't possibly have to do with a certain attractive next-door neighbor wrapping her mouth around someone's pecker, could it?" She giggled and blushed at the same time for being so forward. But she could hardly help but bring it up - for the last several hours she'd been thinking of little else.
"Hey, how did you know that?!"
Katherine lay down on another lounge chair. "Oh, I don't know. A little bird told me. Not to mention the fact that my room is ten feet from yours. I could hear her slurping from a mile away. It sounded like someone finishing off the last of a milkshake with a straw."
"It did not! My room is pretty soundproof, just like yours."
"Okay. True. Maybe I overheard Mom and Aunt Suzy talking about it. I have a feeling they talk about it a lot." In fact, she'd heard a bit of them talking about it, but she'd also listened at his door the night before.
He wanted to know more, but he felt quite awkward discussing blowjobs with his sister. Seeing her in a bathing suit, even if it was a relatively conservative one-piece suit, was enough to get him hard again and drive all other thoughts and moral dilemmas out of his mind. "You look very fetching in that suit," he pointed out.
"Oh, you think so?" She teased, "'Fetching?' What does that mean, exactly? Do you want me to play 'go fetch' with you?"
He just chuckled and made a chagrined face.
Despite the joking around, she was very pleased with the compliment. Until recently, Alan had gone out of his way to avoid thinking about his sister's body. Usually that was easy because she dressed so conservatively. When she would go swimming he'd usually steer clear of the pool because she would get shy and get out of the water when he was around.
The one exception to this was whenever Amy would ask Katherine to pose in a bikini by the Plummer backyard pool so that Amy could sketch her, which was being done to improve Amy's artistic skills and understanding of human anatomy. Many times, Amy would want to sketch Alan in a tight bathing suit as well, which gave him ample time to hang out with Katherine in her bikini (and Amy in hers). However, the last such posing session had been months earlier.
Only in recent days had Alan and Katherine "accidentally" met at the pool. Little did he know that it wasn't an accident, since she had started going out of her way to tease him in her sexy bathing suits.
Seeing Susan spying on Suzanne giving Alan a handjob, plus listening through the door to Suzanne doing it in his room, boosted her self-confidence in taking her teasing with Alan a step further. Burned into her brain was the mental image of Suzanne with her hands sliding up and down her brother's stiff erection. It was about the most arousing thing she'd ever imagined, since she'd actually seen it happen.
Those thoughts drove her onward. She longed to help him with handjobs and blowjobs too, but she still battled with her prudish habits and fears of rejection and of the unknown.
She decided the compliment about her bathing suit was just the opening she needed to do a little more teasing, especially as she knew no one else was yet home. "You may like this bathing suit, but I don't," she pouted.
"Why not?" he asked, taking the bait.
"You've seen the stuff Mom and Aunt Suzy are wearing these days, and I still have to wear a one-piece bathing suit! I need a bikini. Anyways, I've been wearing this one so long that I've gotten some serious tan lines from it." She grabbed the edge of the suit underneath her armpit and pulled it inwards towards her nipple.
"You see right there? You see the tan line?" She kept pulling her suit inwards until her tit popped completely out of the suit. But she acted like that was nothing unusual, and just left her suit that way. "I have to get rid of these awful lines."
"Y-y-yes, I can see," he stammered. "The tan line."
He was shocked, but she was nearly as surprised as he was over what she'd just done. It was as if her hands had minds of their own. She hadn't planned for her teasing to go that far.
"But it's like that all over!" she moaned and pouted. "Look, it's the same on the other side." She pulled on her suit until her other tit popped out. The upper part of the bathing suit was now bunched up in her cleavage.
She looked up at him for his reaction, and was satisfied to see that he was intensely fixated and aroused. So she decided to move on, and rotated her body so he could see her butt while still checking out her naked tits. "Look at my butt too. My tan lines are even worse down there."
She pulled at the edge of her suit along her butt until she'd completely revealed an ass cheek. Then she did the same on the other side. Now her suit was bunched in her ass crack as well as in her cleavage.
He was too stunned to speak.
So she went on, "What do you think I can do about this problem before I get a new suit? The more I'm in the sun, the worse it gets!" She looked at him like this was a serious problem and she couldn't just go out and get a new suit the next day. (In actual fact, she'd already bought another more-revealing suit, but it didn't serve her purpose to mention that at the moment.)
He stared at her for long moments before he realized that she was expecting an answer. He squeaked out, "I don't know." He was having a hard time concentrating on the question. His penis was extremely stiff and his heart was beating fast.
"Oh, wait; I know! I have an idea!" she said happily. "What if I just sunbathe topless? That will get rid of those tan lines."
She pulled her shoulder straps down and off her arms, but kept her swimsuit on from just below her bosom downwards. "That feels better!" she cried out. Grabbing the bunched-up suit below her boobs, she pushed it up into her boobs and out, then began sliding the fabric back and forth. Her completely exposed rack began moving back and forth along with the fabric.
She couldn't believe what she was doing, but she seemingly had no control over her actions anymore; she had been completely overtaken by lust. Just as had sometimes happened to her mother recently, her intellect shut off and she had no idea what she would do next because her lust was in control.
"I know these boobs don't compare with Mom's and Aunt Suzy's. I wish so much they were bigger!" she cried out as she continued to jiggle them. She'd seen how much he was fascinated with Susan's jiggling boobs, so she tried to imitate what turned him on. It worked.
He now stood about ten feet away and continued to come closer, like a moth drawn to flame. He said, "Sis, don't say that! I think your breasts are perfectly fine."
"Fine? Just fine? Aunt Suzy's are super, Mom's are fantastic, and mine are just fine? You might as well say 'adequate'!" She jiggled them even more enthusiastically.
"No, I didn't mean it that way," he protested. "I think you have the best tits in the whole high school. I really mean that."
"Really? But what about Amy? She has those same damn big-boob genes as Suzanne. Not to mention Christine, your love interest. And what about Heather, the head cheerleader? And what about-"
"Hey, just a minute!" He interjected. "Bigger is not always better. There may be one or two who have bigger ones than you, but I still think yours are the best in school." Maybe he was exaggerating a little to make her feel better, but only a little.
"Awww, you're just saying that," she said, delighted. She continued to shake them back and forth. "What about my nipples? Don't you think they're too small?" She put her hands directly on her boobs and began pinching and pulling at her nipples. She tried to keep shaking her tits by rocking her shoulders.
"No, I like them a lot," he said. "Don't knock your body. You have a great body! And your face; it's so lovely!"
She was astounded at his compliments, as he'd complimented her on other things many times but he'd never really complimented her appearance before. That had always been a taboo area.
But she continued to play with him. "Maybe my problem is this suit then. I think it's far too small on me. Look! It barely even covers my most private parts." Leaving her tits exposed, she grabbed her suit with both hands just above her slit and pinched the fabric together so that the edges of her hairy pussy were showing. Then she pulled it up sharply, causing the suit to reposition deep between her labia and in her ass crack.
She began masturbating herself with the suit, moving it up and down repeatedly. She finally fell to the ground and continued pulling the suit higher and higher away from her body. She splayed her legs wide to give her brother a perfect view of her lewd show. She didn't care about anything anymore - it was as if she were possessed.
She began panting and moaning openly. Her legs impulsively kicked into the air. This was easily the most intense masturbatory experience she'd ever had. She had a powerful orgasm that went on and on. She began gasping, "Oh no! Fuck! Oh God!"
Her display was so startling that Alan suddenly became acutely aware that they were outside, and that in theory anyone could be watching. He quickly looked all around, but realized the odds of anyone looking into their remote backyard were between slim and none. He knew that Susan had left to do some errands, but his primary concern was that Susan might return home since it was rare that she was gone for very long. Also, Amy often walked into their house through the back patio, and she could come across them at any time, or merely look out her bedroom window, which overlooked the Plummer backyard.
His gaze returned to Katherine and he saw that she was getting on all fours, as if she wanted to be fucked doggy-style. He watched as she pulled her suit down her legs and stuck her ass up into the air in his direction. What's the deal?! Are all the women in this house total nymphos or something? I can barely wrap my head around what's happening with Aunt Suzy and Mom, and now the same thing is happening with Sis! Dang, we should have tried to solve my energy problem years ago!
"My ass!" she cried out. She wanted to continue the banter with Alan, but she was too far gone to think straight. She lost track of everything except her hand on her butt. She used her hand to rub all over her skin. Her slit was leaking like a river, so she got her hands wet and spread her pussy juices all over her ass.
Finally, she spread her slit for her brother, and then plunged her fingers inside her vagina. She fingerfucked herself as her ass, and in fact her whole body, rocked up and down.
Alan steadily drew closer until he stood over her only two or three feet away. He was tempted to reach out and hold her delicious rear in his hands, but some shred of sanity told him that would lead to disaster.
He thought, I can't touch her - I can't! Once I start on such an obviously horny girl, who knows where it'll end. Actually, I do know exactly where it will end - I'll fuck my own sister! I can't do that! Not only that, but odds are good someone will be home soon. Mom is likely to return from shopping at any minute, if only 'cos she has to prepare dinner. What if she sees us?
So he restrained himself. He even managed to keep his penis in his swimsuit, though he was sorely tempted to masturbate along with his sister. But he could only take so much, and his willpower slipped a little further every second.
She finally appeared to calm down, collapsing completely on the pool decking. She pulled her swimsuit down to her knees, just lying there with her ass still poking up into the air, looking up at Alan and smiling at him. "How did you like the show?" she asked.
But the show wasn't really over. Even as she said this, she put her hands on her snatch and began rubbing it.
She thought, It's like my pussy is itching worse than the worst case of poison ivy, and I've got no choice but to scratch it! I can't believe I'm actually doing this in front of Brother! This must just be an erotic dream; it can't be real.
"Shit. That was amazing, Sis! That is the hottest thing I think I've ever seen!"
She asked, "Remember when we were little kids and played 'show and tell'? Since I've shown you mine, I think it's your turn to show me yours." Sweat poured down her face, and she felt as if she would die of pleasure. She'd never been remotely as aroused as she was at that moment, and wanted to cry out at the top of her lungs in joy.
"I don't know..." he said doubtfully. "What about someone coming along? Amy could walk in, really, at any time..." His resolve continued to weaken.
"Show me your big thick cock!" Katherine barked impatiently. "I'm doing this to help inspire you with your problem, so take it out and jack off! That's what you're supposed to do. Shoot your seed like the doctor says you should! Shoot it all over my ass! Give me your big load! Cover me in cum!" Some tiny part of her brain recoiled in horror at her words, but that part was shoved aside by the larger part that had been hijacked by pure lust.
"Sis, shhh! Someone might hear!"
"I'm going to scream out loud right now unless you show me your dick! Take it out!" Her fingers worked furiously inside her slit. She didn't really mean to blackmail him and she would never have followed through; she was just so overcome with lust that she was ready to say anything to him if it helped her cause.
"Well... maybe... Okay, let's be quick about it." He pushed his boner out the bottom of his shorts and grabbed the exposed shaft with a hand.
"Looks like someone else has a suit that's too tight," she joked. She spoke more quietly and was more subdued, once she'd gotten her wish and could look at his hard-on up close. "Sorry about what I just said. You know I love you and I wasn't gonna scream. But dammit, rub it! I wanna see you jack off! I wanna see you cum. I wanna see you cum all over me!"
She'd been hiding her secret love and lust for her brother for years, but now everything was coming out in the open. This wasn't how she'd imagined she'd reveal her feelings, but events had a momentum of their own.
His resistance faded some more, and he began masturbating out in the wide-open backyard. "Sis, this isn't right," he complained, even as he unabashedly stroked himself. "You're my sister! We can't do this kind of thing. For starters, what if Mom saw?"
"I'm just giving you visual stimulation for your problem. We're not even touching each other!" she said between her ragged panting. Her hand in her pussy was a blur of motion and she was already working up to another orgasm. "But it's not fair: I'm practically naked and you're not. Take it all off!"
He pulled his swimsuit off and threw it aside. He justified it to himself by figuring that it wasn't hiding anything anymore anyway.
Both of them continued to masturbate mere feet from each other.
"Let's just not get caught," she said after another minute or two. "Besides, you seem to be enjoying yourself. Do you like to watch your horny little sister cum? I'm cumming for you, Bro! For you!"
In fact, he was about to orgasm despite his best efforts to hold it off.
She had no such need to hold off, and began another whole series of small orgasms.
