Primal Atavism

He reaches my cervix in one glorious stroke. There's no slow start, no build up; he just grabs my hips and pounds me into the wall. I cry out with each thrust, aware that the neighbours will hear, but not caring one bit as spasms of pleasure overwhelm my body.

'Oh god. Just like that.'

My words are like crimson to a bull. He grabs my hair—a thrilling surprise—and pulls my head back as he fucks me harder.

'You like that?' he growls.

I respond with a high-pitched squeal, every nerve-ending in my loins ablaze as he stretches out my insides, reaching the point where my orgasm demands release. I open myself up to it, willing it to come, but as always, it doesn't quite arrive. He continues to thrust, and despite my body's denial, I grin at the wall as his cock swells.

'Fuck Rachel...'

The surrender in his tone lets me know he's almost there. I push my arse into him and, with no small effort, find my voice.

'Cum for me,' I beg.

He crumples into me, and I savour the heat and sweat of his body as he erupts in my pussy while moaning his pleasure.

As we recover, our heavy breaths a din in the quiet of the empty flat, I can't help smiling at how naughty I've been—how he was supposed to give me a tour, yet we ended up fucking mere steps from the door. He spins me around and, after a few seconds lazy kissing, breaks into laughter.

'What?' I say.

'Nothing, I just had no idea you were so wild.'

'Are you complaining?'

With a squeeze of my arse he kisses me again. 'What do you think?'

He opens a bottle of wine and we curl up on the sofa. We both profess our interest in bizarre documentaries while scrolling through Netflix, so we put one on about the leader of a Christian cult in Utah, who just so happens to have been told by God to sleep with all the women in his community. I've seen similar stuff before, but it's nice to chat and laugh about it with someone I get along with so well—and the fact the date's still going wellafter having sex is an encouraging sign.

'Would you smash?' he asks when the ponytailed cult leader appears on the screen.

'Eww no, he's about sixty.'

'I know, but if you'd been brought up there and truly believed he was the messiah, don't you think you'd want to?'

'I'd have to be pretty indoctrinated, but even then...'

'You'd just have to close your eyes and think of me.'

I scoff. 'A bit full of yourself, aren't you?'

'You're not denying it.'

He slips his hand under my dress to the front of my underwear. My pussy's still wet from earlier, and his touch sends a shiver through my loins. I pull my knickers aside to give him access, and he continues what he started in the hallway. My concentration on the documentary wanes, and soon I want more than his fingers.

'I don't have another condom,' I mumble between groans.

He turns my head and kisses me on the lips. 'I'll be right back.'

He gets off the sofa and jogs to his room, returning only a few seconds later with the packet already torn.

'I've never seen anyone move so fast,' I tease.

He gestures to the TV. 'Can't leave you alone with him for too long.'

I laugh as he repositions himself behind me, and after a little more foreplay, we're having spooning sex in front of Utah's self-proclaimed messiah. It's more sensual this time, the bulk of our energy having been expended against the wall. We make out as he kneads by breasts while treating my pussy to long, slow strokes. After he climaxes a second time, we finish the documentary in sleepy contentment.

By the time we make it to the bedroom we're too tired to do anything else. I slip out of my dress, and Greg lends me one of his t-shirts that ends up looking comically baggy on my frame. I cuddle up to him and close my eyes, enjoying the warmth and safety of his arms. It's the happiest I've gone to sleep in a long time; not just because of the great sex, but because I've finally found a guy post-Jason whom everything seems to click with. Too good to be true? Maybe, but if I haven't seen the inside of his closet, there's no point assuming there's a skeleton.

As I'm surrendering to sleep, I frown at a peculiar thought. Dylan, with his improved posture and folded arms, wanders into my mind, along with the compliment he was so embarrassed to let slip.I've just never seen you look so beautiful.

I don't know why that popped into my head, but I'm too tired to figure it out.

*

'Twice?' Aleisha exclaims.

I nod, unable to keep the grin off my face.

'And you didn't even get to the bedroom?'

'Keep your voice down,' I whisper, looking around the bar to make sure no one heard. 'Nope.'

'My bad. That's amazing though, it's about time you had some passion in your life. How was it?'

'Amazing'

'So the journey was great, but did you arrive at pleasure city?'

I sigh, the smile leaving my face for the first time since sitting down. 'Not exactly.'

'Damn, Rach... ' She gives me a look of almost pity. 'I wish I knew what was stopping you.'

'You and me both.'

'Are you sure it was that great?'

'Positive. I cameso close, but I just couldn't quite... Ugh, I don't know what's wrong with me.'

'Absolutely nothing,' she assures. 'I bet when you get to know each other better, you'll be humming like a housewife on a dryer.'

I burst out laughing. 'I hope you're right. Anyway, it's your round.'

'I'malways right. Same again?'

I nod, and she returns from the bar a couple of minutes later with two white wines. 'I meant to ask, how's Dylan's trial going? Is he a Lothario yet?'

'Not quite, but I have noticed a few differences.'

'Ooh, do tell.'

'His posture is better, he's sticking his chest out more. And... Never mind, too much information.'

'Go on, you can't leave me in suspense.'

'Alright.' I lower my voice. 'He's masturbating.A lot.'

'Wow. And you think that's the drug?'

'It must be. Unless it's a placebo effect. Either way, it's only been two weeks since he took it. I dread to think what he'll be like in two more.'

She gives me a puzzled look. 'What makes you say that? It sounds like he's made an improvement.'

She's right, and I should be happy for him. Iam happy for him. It's me I'm worried about. Thinking about him while in bed with Greg has been niggling at me all week. 'I'm not sure I even want to tell you this, but something weird happened.'

'What do you mean, "weird"?'

'When I was in bed with Greg...I thought about Dylan.'

Aleisha splutters on her wine. 'Oh my god, while you were...'

'No. After, while we were cuddling.'

'Oh. Isn't that kind of normal? I think of my sister at random times. Plus, you are worried about him, it's only natural to hope he's okay.'

'Yeah, but it wasn't just an "I hope he's okay" kind of thought.

'Sexual?' she whispers.

'No. I don't know. Appreciation, maybe.'

'I think you're overthinking this, Rach. I wouldn't worry about it.'

Unconvinced, I give her a wry smile. 'You're probably right.'

Dylan

It's been almost a week since the incident atPapertrail, and I'm on the cusp of going mad. One minute I feel like I'm getting used to my new libido, then the next I'm consumed by it, unable to concentrate on anything else. I even emailedPothos about it, who responded by saying it was an expected effect of the drug, but I should monitor it and let them know if it becomes intolerable. Over the last couple of days, there have been times when it has been.

'You've barely left the flat this week,' Rachel says over breakfast. 'Are you sure everything's okay?'

'Fine, honestly. You don't need to keep asking.'

'Are you still thinking about what happened in the book shop?'

I give her an acrid look that tells her to drop it.

'Okay, I get it. I'm not your mother. On a different note, Aleisha's going to be staying over on Saturday.'

'How come?' I say a little too keenly.

'That perked you up,' she teases. 'She's flying to Nigeria for her cousin's wedding on Sunday morning. We're closer to Heathrow, so she'll be in less of a rush.'

I try to level out my tone. 'Makes sense.'

'Right, I'm going to be late for work. See you tonight.'

I jump in the shower after she leaves. For the first time, I have mixed feelings about Aleisha. While my usual anticipation is undiminished, it's laced with the trepidation of not being sure how I'll handle her in my current state. I chuckle at the thought; ifPrimal Atavism can make me comment on a random woman's boobs in a bookshop, seeing Aleisha might cause me to break into song.

On the bright side, she'll provide a much-needed distraction from Rachel. The inappropriate thoughts about her haven't gone away, the only mercy being they aren't constant...yet. Most of the time she triggers them unknowingly, whether it's her pyjama shorts, seeing her wrapped in a towel after a shower, or helping her pick an outfit for a date like I did the other night.

Speaking of her date, she didn't make it home, which means only one thing. I lay awake in bed for hours, and the longer the front door remained unopened, the more thoughts of what she could be doing plagued me. I must have counted thousands of sheep, horniness better than any amount of caffeine at staving off sleep.

As I savour the warm cascade of the water, my insatiable loins demand attention. A shower hadn't featured in my thoughts at the time, but with the whole night to themselves, it's an intriguing possibility. Before I can consider how wrong it is, I imagine away the towels I've seen Rachel in, revealing first her damp hair, then her sumptuous body. Greg is there too—or perhaps it's me—drinking in the sight. She raises a finger, beckoning me—Greg!—towards her.

Giving in to temptation, I wrap my hand around my hardening cock. A sensuous shiver is my perverse reward, belaying my brain's pleas not to do what I'm about to do. I might have stopped a week ago, but salvo after salvo of carnal thoughts have desensitised me to all misgivings.

I stroke myself to a granite-like erection over Rachel's wet, naked body, imagining a sultry smile on her face as she crouches on her haunches and takes Greg's cock between her lips. I draw out the pleasure, enjoying the taboo sensation for nearly half an hour until the stream begins to cool. Before it goes completely cold, I pump past the point of no return, abandoning my pretence that it's Greg she's sucking off. Whispering my sister's name, I paint the shower tiles with an incredible orgasm, each shot euphoric as I envision it disappearing down her throat.

I open my eyes to the soiled wall, gooey globs of white trickling towards the drain. What the fuck have I done? I've crossed a line that should never be crossed, all for the fleeting pleasure of awank, and my perception of Rachel will probably never be the same. Curling my lips in disgust, I snatch the shower head from its bracket and hose down the wall, desperate to erase the evidence of my deed, then finish washing as quickly as possible and flee the scene. I fling open my bedroom door and kick my bedpost, ignoring the pain that follows. How can my feelings for her be getting stronger? I've always thought humans evolved to not be attracted to their relatives. There are exceptions to the rule, of course, but why would a drug designed to reawaken dormant traits damage the failsafe against familial attraction?

Could it just be me? Are the other participants in the trial hormonal messes, or didPrimal Atavism work for them as intended? I wish I could ask them, but in the absence of that, I open my laptop and type an email toPothos in search of answers.

To their credit, it takes them just over an hour to reply. Their response is detailed but, ultimately, unencouraging. As I expected, it starts by saying they can't disclose details regarding other participants. The more interesting part relates to my concerns about Rachel.

You're right when you say that human beings have evolved a sexual aversion to blood relatives. One hypothesis for this is the Westermarck effect, which postulates that people who live with each other in the first few years of their lives are desensitised to sexual attraction.

There is, however, a controversial theory known as genetic sexual attraction, which states that it is not uncommon for family members who meet later in life to develop sexual feelings for one another. There is relatively little research around the concept, which has been criticised by some as pseudo-scientific. As you grew up with your sister, it does not seem likely that this phenomenon, should it exist, would explain your feelings.

Having said that, there is a possibility thatPrimal Atavismmay be interfering with the evolutionary barriers against familial attraction. During the computer simulation phase of the drug's development, we found nothing to indicate that this would be the case, although our software is unable to simulate the drug's effects on the human body with 100% accuracy.

We advise you to monitor your situation, and to contact us immediately if your experiences are in any way impairing your physical, mental, or emotional wellbeing.

We hope we have sufficiently answered your question, and if you have any further queries, please do not hesitate to ask.

Intrigued, I clue myself up on the Westermarck effect and genetic sexual attraction. While both topics make for fascinating reading, neither seems pertinent to my situation, and reading the email between the lines, it's apparent they have no conclusive explanation either.

I go to the bathroom to double-check everything is cleaned up before Rachel gets home, then try to forget about the episode and get on with my day.

*

'Dylan,' Rachel says, knocking on my bedroom door.

'Yeah?'

'I want you to come to the supermarket with me.'

'Why?'

'Because you haven't left the flat in over a week.'

'I went out yesterday while you were at work,' I lie.

She's silent for a few seconds. 'You decent?'

'Um-hm.'

She opens the door and sits on the end of the bed. 'What's wrong, Dyl? And don't say "nothing", because I'll know you're lying.'

I turn from my desk, interrupting my third self-report form toPothos.

'I'm fine, honestly. It's just been a difficult adjustment since takingPrimal Atavism.'

She nods, fidgeting with her hands. I sense she's got a burning question that she's unsure whether to ask.

'What is it?' I say.

She sighs. 'Don't hate me—I'm only asking because I'm worried about you. Is it because you're horny all the time?'

The words pour over me like icy water. Of all the things I never wanted to be asked by my sister, that has to be near the top of the list. Judging by her immediate embarrassment, a look to match how I feel is strewn across my face.

'Shit, I'm sorry,' she fumbles. 'I shouldn't have asked. It's just you've been...you know...a lot and—'

'It's fine,' I interrupt before she digs herself a deeper hole. 'You're not wrong, but it's an expected side-effect of the drug, so there's no need to worry.'

Mortifyingly, she persists. 'I know how guys your age get. It's normal—healthy, even. But it shouldn't make you withdraw like this. Are you sure there's nothing else to it?'

Telling her the truth would make her wish she'd never asked.Well now you mention it, Rach, there is. A few days ago, I had a wank thinking about you sucking me off in the shower, and there are times when I can't get you out of my head. Happy now? In the interests of not ruining our relationship, I go with a different reply. 'I'm still getting used to it, that's all. And it's a bit demoralizing when the only changes seem to be negative.'

'Are you kidding?' she exclaims.

'What do you mean?'

'You seriously haven't noticed?'

'Noticed what?'

'There havedefinitely been positive changes. You're standing up straighter. You're sticking your chest out and walking with more of a swagger. You have more of a presence than before.'

'What kind of presence?'

She puffs out her cheeks. 'I don't know, it's hard to describe. More masculine, I suppose.'

I raise my eyebrows.

'Not that there was anything wrong with you before,' she quickly adds. 'Objectively, though, I think it's a good thing, especially from a woman's point of view.'

'I had no idea... And you're not just saying that to make me feel better?'

'Absolutely not. I wouldn't lie to you about something like that. I've even mentioned it to Aleisha—you can ask her when she gets here. Speaking of which, I need to go shopping now so I'll have time to cook dinner. Please come. It feels like you've been avoiding me lately, and it'd be nice to spend some time with you.'

As much as going to the supermarket is the last thing I want to do, I can't say no to a guilt trip like that. 'Alright. On one condition.'

'What's that?'

'You never mention my...you know...habits again.'

She smiles. 'Deal. I'll even let you pick dessert.'

'Give me ten minutes to finish my form, then I'll be ready to go.'

She thanks me and leaves me to it. I don't turn back to my laptop straight away, too busy staring at the depression in the duvet where she was sitting. I close my eyes despairingly as my pulse rises, the fact she was on my bed evoking a storm of illicit thoughts.

Shaking my head, I spin my chair and type out the last couple of paragraphs.

*

Surprisingly, the supermarket turns out to be just what I need. Pushing a trolley around while Rachel adheres to her fiercely organised list serves as a welcome change to the flat's four walls. I've never seen anyone shop like her. The items have to be taken in the exact order they're written, and every steer of the trolley down the wrong aisle earns me a telling off.

'You're the only person I know whose shopping method I'd describe as fascistic,' I say.

'It's not fascistic. It's correct.'

I snatch the list from her. 'It's not even organised by category. It's based on the floor plan of the supermarket.'

'Exactly. It's the most efficient route, meaning I finish in the shortest time possible.'

'What do you do when they reorganize the shelves?'

She looks at me with mock-seriousness. 'I adapt.'

As we continue through the aisles, I can't help but amuse myself by deliberately going the wrong way.

'I know what you're doing,' she says.

'Hey, you wanted me to come.'

'Don't remind me.'

As she turns down the dairy aisle to get milk and butter, it strikes me that for the first time in ages, I've gone an extended period of time without being preoccupied byPrimal Atavism-related thoughts. I'm smiling at the banter we're having, and it's a relief to go back to seeing her as just my sister, although I'm not sure how long it will last.

'Right, I promised you could choose dessert,' she says after putting the last item on her list into the trolley.

I lead her to the bakery aisle and stop in front of what I want.

Her expression is unamused. 'That's a caterpillar cake...'

'I know.'

'You enjoy winding me up, don't you?'

I flash her a grin. 'Is it that obvious? Profiteroles would be great.'

'Now that's what I was hoping you'd say.'

We find an empty checkout, where the girl behind the till looks weirdly pleased to see us. I soon see why. She looks younger than the rest of them, and there's a sign next to her that reads:In training. Please be patient.

'You looked lonely over here,' I say.

She smiles. 'Yeah, tough being the new girl.'

'How's training going?'

'Alright. A little slow. There's a lot more to it than I expected.'

'So you're not like Vince inEmployee of the Month yet?'

'Is he the guy who does fancy tricks at the checkout?'

'That's the one.'