Expensive Upgrade

As the clock continued to tick down, Libby couldn't conceal her wicked grin as she looked down at his throbbing cock as she allowed the tip of her tongue to brush against her lips. "Did you enjoy me showing you those pictures earlier? All those little outfits...there's so much more that I'm going to show you... I chose every single one of them because I wanted to get that big dick nice and hard for me... It's only been a matter of time, Callum... Ever since you saw me walking into that hot tub in that tight fucking bikini...there's no way that you're going to be able to stop thinking about me... Tell me something though, if you're so happy with Fiona...why are you thinking about me in this gorgeous little lingerie set? I'll tell you why, it's because when that dick gets so fucking hard...it's because you want to feel it slide into my tight little pussy while I put these big tits right in your mouth..."

The sinful accusation only compelled Callum's dick to throb with approval as he took a deep breath. Even hearing the fantasy version of his sister say those words out loud was enough for him to want to reach down and start massaging his hard cock, but the rational parts of his brain were screaming at him to compose himself. So much of him knew that he could never jerk off to his sister, that if he did so he'd be crossing a line that he could never return from. After he gasped, Callum looked into her eyes and replied. "If you're really in my head, you'd know that I've never thought about that for a second... We can't do this, Libby... We both know how wrong it is, it doesn't matter how beautiful you look... It doesn't matter how fucking hot you are... I can't think about you when I'm like this... I can't think about you when..."

Despite his protestations, Libby stopped him dead in his tracks as she stepped closer and straddled his waist. After hovering for a few moments, Callum's sister lowered her hips decisively and sat squarely in his lap as she allowed herself a long glance at the clock over her right shoulder.

With just over 45 seconds remaining, the scheming redhead turned and looked her brother in the eye before she purred at him. "Doesn't that feel better? That big hard cock is so close to my wet little pussy... You don't need to fight this, there's nothing wrong with knowing what you want... The way you want me to peel this bra off and for me to feel your tongue against my hard nipples... The way you want me to lean in for our very first kiss, while your hands clutch and grope at these big tits... The clock's counting down because your mind already knows what you're going to do... Believe me when I tell you, Callum...knowing that you're thinking about me while you're jerking that big dick...it's so hot, babe... What other sisters walk around in front of their brothers like I do? All those stories about me having the wildest sex... Don't try and deny it, you know the truth... You know that I want you just as badly as you want me... We're perfect for each other..."

Carefully, Callum turned his head to look at the enormous clock as it ticked ever closer to zero. When only five seconds remained, Callum felt Libby's fingertips under his chin as she turned his head to face her once again. As she looked into his eyes, her head started to lean in as she whispered to him. "I don't care about Fiona, nothing's going to stop me from riding your big dick until I explode..."

The words barely had a chance to register within Callum's mind as he felt Libby's plump lips colliding with his within his perverted fantasy. But as he lay atop his bed in reality, the moment where the countdown reached zero was when Callum was powerless to stop himself from stroking his hard length as he imagined Libby's tongue slipping past his lips until it was writhing against his. His eyes were closed so tightly and his breathing was ragged, but the sheer pace of how he started pumping his hand across his cock signified just how complete his surrender truly was.

Within his fantasy, Libby controlled every moment of the kiss as she let her tongue delve deeply into her brother's mouth before it slowly withdrew. As she reached behind her back with both hands until she found the clasp of her bra, she unhooked the tight lace garment with ease as she pulled the bra from her upper body and tossed it down onto the floor behind her. Once Callum was treated to the sight of his sister's wonderful tits, with her tiny pink nipples swollen and pleading for his affections, his whole body froze as Libby leaned in and brushed her hard nipple against his lips.

While one of the glass walls had been replaced by the giant digital clock, Callum was only vaguely aware of the engineers who had left their stations and were thumping against the glass with all of their might. Each one of them was calling out to him, desperately trying to force him to come to his senses and break free of his sister's seductive spell. But once Callum's lips closed around Libby's tiny bullet nipple and he began to suck, more jets of steam and plumes of smoke were released into the room. The scene had started to resemble a control room in the moments before a devastating meltdown, one where the consequences would be irrevocable.

When Libby felt Callum's lips and tongue worshipping her breasts, she leaned down and wrapped her hand around his hard cock. Carefully, she positioned it until his bulging head was pointing upwards before her other hand ripped her tiny lace G-string clean off her own hips. It was then that she waited until Callum's eyes opened before she dropped her hips once more and took his rock-hard dick so deeply inside her tight wet pussy.

Meanwhile, as he lay atop his bed back in reality, Callum could only process the end of his sick fantasy for a few moments before it drove him so far over the edge. With his hand jerking and pulling at his hard cock, his eyes opened wide as he couldn't stop himself from groaning into his empty bedroom as he shot the first of many ropes of his warm seed up into the air. His heart felt like it had stopped due to the intoxicating combination of his monumental orgasm and the knowledge that he'd just masturbated to his gorgeous sister. But as his cock spasmed and shot the remainder of his cum up into the air, Callum sensed how much trouble he was in as he'd simply never experienced an orgasm like it in his entire life. Once he was able to suck down enough oxygen to think clearly, Callum was left in no doubt, whatsoever, that he was starting to lose his mind.

The following night, Callum found himself standing in the corner of a busy bar in Glasgow City Centre. It was just after 10:00 p.m. and both he and Libby had spent the last two hours catching up over drinks as they'd previously agreed to. The bar which Libby had chosen was quite trendy and popular with young professionals, and Callum only needed to look around to see that the clientele was classier than that which frequented the many different student bars across the city. However, despite it being a Sunday night, the bar was much busier than either of them had anticipated and they'd snuck off into a corner where there was the most space available.

As he was stood leaning back against the brick wall behind him, he'd taken Libby's advice and chosen to wear a nice black long-sleeved shirt which he'd paired with his favourite light-grey trousers and black shoes. He knew that he looked good when he stared at his reflection in the mirror before he left, but when he finally saw his sister wearing her outfit in the flesh, he started to understand just how Libby had influenced him to such a degree that he'd started playing with his hard dick while he thought about her.

Libby's gold shirt looked sublime as her long sleeves were rolled up past her elbows and the garment looked to be much tighter than it did in the preview picture. But every time the two were engaged in conversation, Callum struggled to maintain eye contact with the beautiful redhead as her shirt was purposefully designed to show off her incredible cleavage. Each time she twisted or turned her upper body, Callum was treated to the most delightful bouncing of her breasts as the tight black lace bra did its best to contain Libby's prized new accessories. Meanwhile, whenever the hem of Libby's tight miniskirt rode fractionally upwards, Callum was afforded a tantalising glimpse of the same black lace stocking tops that he'd pictured his sister wearing in his impromptu fantasy.

In that moment, Libby was stood facing her brother as she took a slow sip from her drink before she sat it back down on the table next to them. With a grin on her face, she looked into Callum's blue eyes and spoke. "See? I told you she was absolutely gorgeous, didn't I? I know she said she could only drop by for a half hour or so, but I really don't think she's going to be in any hurry to go back to her friends. Isn't it hilarious though that she thinks we're a real couple?" The comment coaxed a soft giggle past the redhead's lips as she failed to disguise the glint in her eye before she continued. "I only need you to play along until she leaves, but you should take it as a compliment... If she believes you're pretty enough to be dating me, that's quite a high bar to clear..."

Despite his mind having been pulled in a million different directions since Libby walked back into his life three nights earlier, his sister's quip was enough for Callum to start laughing as he appreciated the humour of it. Once he looked into her eyes, he replied. "Don't get me wrong, Alicia's absolutely amazing...she's everything you said she'd be and more... I guess that I'm just a little surprised that she's your type... Not that I'm saying I know what your type is...but the tattoos and the fit muscular body wasn't what I was expecting. Fiona would kill me if she heard me saying this, but I can't remember the last time I saw someone look as good in a dress as Alicia does..."

Hearing her brother's reaction was enough for Libby to tilt her eyebrows in appreciation as her smile widened. After a brief pause, Libby replied. "She's obviously hot as fuck, but it wasn't until I started messaging her that I realised there was more to her than meets the eye. I think she realised quite early on that I respond really well to my partner taking charge of me... I'm not normally the submissive type, but when Alicia flirts...she makes it very clear that she likes to be in control... It didn't take her long to send me pictures of stainless-steel handcuffs before she'd say that they were just for me... I wasn't sure if we'd ever get to the stage where we'd actually meet, but when she walked up to us in that gorgeous dress...I'd knew straight away that I'd let her handcuff me to any bed she wanted to..."

Callum never had so much as a moment to prepare himself for Libby's heated comment and it resulted in him feeling a pang of approval from between his legs. It had only been three days since he'd been reunited with his beautiful sister, but she'd made so many lurid comments that dripped with innuendo that he couldn't stop himself from becoming aroused each and every time she did so. But as he pictured the image of Libby's incredible body writhing in the tight cuffs as she was bound to his headboard, Callum had to shake his head briefly to bring himself back to his senses.

With his back still leaning against the brick wall, Callum responded as best he could. "You're going to need to tell me what I'm supposed to say if she asks any questions about us. If she thinks that we're a legitimate couple, have you told her anything about us that I'd need to know? All you told me so far is that I'm supposed to know all about how you pick up girls like her on dating apps...and I'm fine with it... Mind you, if Fiona ever brought someone like Alicia home, I don't think I'd be able to last long enough to get her out of that dress... She looks incredible..."

After she turned her head to look towards the bar, Libby smiled as she saw Alicia returning to where they were standing with their three drinks in her hands. Quickly, she turned back to face her brother as she responded. "Don't worry about any of that, she's coming back over. Just follow my lead, she hardly knows anything about my supposed boyfriend. I only told her I had one because she was coming on so strong at the start, I was trying to find a way to give myself an escape route that made the most sense. But when I told her I was seeing a guy, she just told me that it made everything so much hotter for her. I'm telling you now, Callum...she's kinky as fuck... I honestly don't think she'd give a fuck if she knew we were actually related..."

The next hour passed as Alicia stayed much longer than she originally intended to. Once the clock moved past 11:00 p.m., the three of them remained in their spot in the far corner of the bar while their drinks rested on the table next to them. The only change to their immediate surroundings was that more customers had ventured inside the bar, which made it easier for the three to blend in.

As Callum remained in his spot leaning against the brick wall behind him, Alicia was stood facing him as Libby had positioned herself to his right-hand side. Once Alicia turned her head to address his sister, Callum had ample opportunity to appreciate the sight of the mysterious girl who'd made no effort to conceal her attraction to his sister. Alicia was the same height as Libby, standing at 5'7", and her body was almost poured into a wonderfully tight blue dress. While her breasts were only fractionally smaller than his sister's, her natural chest was supported by a matching blue bra that the thin straps of her dress made no attempt to conceal. Meanwhile, the plunging neckline of her blue dress displayed a cleavage that had almost every man in the bar breaking his neck to appreciate whenever she walked past.

However, as Callum caught himself staring at the girl, it was the smaller details that really added up to give her the unmistakeable aura that she possessed. Her long dark hair was deliciously wavy and afforded Alicia a carefree look as it flowed all the way down to reach the top of her tight ass, while both of her arms were almost entirely covered in various tattoos which never threatened to detract from her sensuality. Meanwhile, her plump lips looked sensational as she purposefully wore heavy makeup that made her lips and eyes stand out in the most alluring manner. As Callum's eyes roamed across her face, he kept being drawn back to a small mole on her left cheek which accentuated her look perfectly. But as pretty as her face was, her body was undeniably world class. Her shoulders, back, legs and ass were all toned and strong, which let Callum and Libby know that she spent more than enough of her time in the gym. After Callum glanced back up and dragged his eyes back up her body, her simple black plastic choker was the perfect finishing touch as he struggled to tear his eyes away from it.

He'd only zoned out for a moment, but Callum had lost track of the girls' conversation when he caught Alicia turning her head back towards him to speak. "You know, Callum...when Libby told me that she was seeing someone, I knew that he'd have to be quite something to hold onto a girl like that. But you've got no idea how relieved I was to hear that you two are in an open relationship, because once Libby sent me that first message and I saw how she looked in her pictures...there was no way that I was ever going to let her get away from me... It's cool what you're doing though, I haven't been in an exclusive relationship for years. When I was on my way here tonight to meet you, I didn't know what to expect...but looking at you now, Callum... You're fucking gorgeous... Now I understand why Libby keeps boasting about how much time you two spend fucking each other's brains out..."

The compliment caught Callum completely off guard, but when he tried to process the kind of things that Libby had told her about him, what they'd gotten up to in bed with each other, it sent a rush of blood between his legs. He'd barely managed to come to terms with the fact that he'd spent an entire afternoon in bed jerking off while thinking about his sister's scalding hot body, but the very idea that Libby had told the glamorous Alicia that they'd been having sex just made Callum wish he was alone in his bedroom once more.

While his thoughts were scattered and racing through his head, Libby giggled as she stepped directly in front of Callum until her own tight cheeks were pressing against his groin. As Callum was leaning against the wall, he had no room for manoeuvre as he watched his sister look into the brunette's eyes. At that moment, he was almost floored by the way that Libby allowed herself to lean back into him until her ass was practically grinding against his cock, before she reached out and placed both of his hands squarely on her hips. From his position, he had the perfect view to peer down Libby's stylish gold shirt as he saw almost the entirety of the redhead's black lace bra as it struggled to contain her exquisite breasts. Instinctively, Callum tried to drive his hips forward to create some separation, but once again Libby surprised him by playfully pushing her cheeks backwards to trap him in place against the wall.

Callum knew that Libby wanted him to play along, but he started to panic as his cock couldn't be controlled as easily as his hands were when his sister placed them on her hips. As his eyes started to narrow, the realisation that Libby was about to feel the full force of his throbbing dick pressing against her was threatening to tear his mind apart.

At that stage, he heard Libby starting to giggle as she stared into Alicia's eyes and spoke. "Oh, I know just how gorgeous he is...and he's all mine... I know how lucky I am though that he lets me meet up with other girls... One of the first things he told me after we started dating was that nothing gets his big dick harder than seeing me in bed with another woman... It's not something that we've done a whole lot, but whenever we have...it's just so hot knowing how hard he gets watching me lick another girl's pussy... All it takes is for me to have one little kiss with another girl and he's ready to fuck me for days afterwards..."

Callum was so shocked at the bold statement that escaped past his sister's lips, to the point where his eyes wanted to dart all over the place. However, once he made eye contact with Alicia, he saw the sultry look on her face as she was delighted with what she was hearing. As Callum stared at her, Alicia looked into his eyes and responded. "Is that right, Callum? Well, trust me when I tell you this, you won't have to wait very long before you see your girlfriend's tongue slipping across my tight little pussy... Libby and I have been texting for almost a month and I can't wait to get my hands on her perfect body... I'm going to need to leave here in a few minutes as my friends are waiting on me, but I hope you don't mind that Libby's already invited me over to your place on Tuesday night... She's practically begged me to bring my handcuffs with me, so I can't wait to see how hard that big dick gets when you watch me ride your girlfriend's pretty face... Having said that, after meeting you tonight, Callum... Just thinking about your hard cock driving inside Libby's pussy has got me so fucking wet..."

Slowly, Callum's jaw started to hang as he felt like he'd been separated from his senses. So much of his mind was calling out to him, silently assuring him that this was all a misunderstanding because of Libby's insistence that they pretend to be a couple. However, the absolute conviction of what his sister and Alicia had purred at him was so strong, Callum felt like he could taste it at the back of his throat. But as shocking and as direct as Libby's taunting was, the moment Callum dreaded had arrived as his cock was completely hard and throbbing. When he felt Libby press back against it until her cheeks brushed across his entire length, his eyes started to narrow as he braced himself for her horrified reaction.