Sorority

Warning: this story is a fantasy and details sexual behaviour that is, at best ill-advised. But it is pretend, so so long as you aren't a doofus, you should be ok. All sex-acts described are within ages of consent in the country it's written in (England, for the record).

This is also an introduction, and the next part is already conceived and can be out soon if I get some positive comments that anyone wants to read it!

For the third time in the last five minutes, Penny silently scolded herself and tried to focus on the movie on TV. Ok, so they were actually only step-sisters but she'd known Natalie since she was five, and the way she'd been looking at her across the sofa was all wrong. Apart from anything else, Penny had never looked at any girl that way – she may've been single at the moment, but she'd had a reasonable share of men at uni, and they'd had a reasonable share of her. But Natalie was fascinating her...

As she tried to ignore her desire to look, Penny's mind puzzled at why she was looking at a girl she considered a sister in such a weird way. Maybe it was how different they now were. When they met thanks to Natalie's dad and Penny's mum, they were five and nine, and both kids. Besides, Penny's actual sister was there too, and they formed a close family unit and were all basically kids. Sure, as they grew the fact that Penny and Hannah (her elder sister) were slim with glossy, black hair and pale skin, whilst Natalie was a more tubby kid with tumbles of deep, auburn hair, made it clear that they were not blood relatives, but they behaved as if they were. Now however, at 19, Natalie had very much grown into her body. Penny (23) and Hannah (25) were almost exact replicas of each other, and were often mistaken as twins at a glance. Penny had C-cup breasts to her sister's Ds, but also had an eye-catchingly spankable bottom compared to Hannah's more slender butt, but they were both a slim size eight and shared clothes between themselves. Natalie, though a similar height and still with a slim frame, was altogether more voluptuous. Though her waist was slim and toned, her hips flared out to a full, curvy bottom necessitating size 12 jeans, and despite her slender back, she'd grown big, soft, F-cup boobs. And it was at these, or more specifically the deep cleavage formed by the way she was splayed on the sofa, that Penny found herself staring.

Dragging her eyes once more from her sister's breasts, and trying to put the strange thoughts out of her head (What would Natalie look like naked? What did she like in bed?), Penny downed the remainder of her glass of white wine and poured both girls another, smiling at Hannah as she walked in from the kitchen. Both Natalie and Penny were staying with Hannah over the Easter holiday. All were single, as it happened, and were enjoying spending time together, shopping, drinking and spending time together. Resolute now, Penny gave all her attention to the movie and clamped down on her odd thoughts – she needed to forget all about this as she'd be sharing Hannah's spare bed with Natalie in an hour or two!

Hours later, Penny woke up. She'd always been a light sleeper, and slept even less well in unfamiliar surrounds. The clock-radio told her it was a little after 5am. Rolling over, she found herself looking again at Natalie. It was warm in the house, but modesty had led both girls to sleeping in flannel pyjama bottoms and tank tops. The pre-dawn light in the room was enough for Penny to see that Natalie had thrown back the duvet in the night. The younger girl was laying on her back, legs twisted towards her step-sister, with her head on one side. Her deep, even breaths made her big boobs rise and fall as she slept soundly. She seemed to be dreaming, though, as Penny watched her. Natalie was frowning in her sleep, and stirring gently.

Almost without conscious thought, Penny reached out with her left hand and carefully, almost imperceptibly, cupped Natalie's right breast. She left her hand still, to see if Nat would stir further, but when she didn't she slowly grazed her palm and fingers over her younger step-sister's chest, feeling the swell of the big breasts beneath the thin fabric of Natalie's top. As Natalie remained sleeping, Penny grew bolder, softly cupping and stroking the big, soft tits. Natalie's nipples began to respond, stiffening in the tight top, raising two hard points in the material. Penny assumed this was involuntary and continued to gently fondle her step-sister's boobs with her left hand, whilst her right slipped under the waistband of her pyjamas and began to stroke her own sopping pussy. She was scandalised and terrified almost as much as she was excited by how wet she was, somehow more turned on by this almost incestuous lesbianism than she ever had been by a boy.

Penny rubbed herself off in no time at all, turning her face into her pillow to stifle her moans as she came, and making sure that she didn't clutch at Natalie's breasts in her excitement and accidentally wake the younger girl.

No sooner had she come than she was washed with guilt. What had she done? What was she thinking? Bringing herself off whilst groping her younger step-sister? A girl she'd known when they were both at first school! Fuck! But all the guilt could not change the fact that Penny's pussy was still tingling and her own, pink nipples were painfully erect on her perky breasts. Carefully rolling onto her back, Penny dozed off into a fitful sleep, troubled with dreams, equally sexy and guilty.

For her part, Natalie kept her eyes closed and lay still until she was certain the dark-haired girl she considered a sister was definitely asleep. It had taken all her self-control not to open her eyes when she'd been awoken by Penny's obviously intentional stroking of her boobs, never mind when she'd heard the clear sounds of a pussy being rubbed and the muffled sounds of Penny's orgasm. Once Penny's breathing had become slow and deep, however, Natalie opened her large, green eyes and looked with clear lust at Penny. As the youngest, Natalie was seen by her sisters as the child of the family, and they presumed a degree of innocence on her part that had not been there for a good few years. She still played the part of cheery klutz at home, as was her defined family role, but once away from her family, Natalie had an altogether different reputation.

As soon as her breasts had turned from promising to staggering not long after she turned 16, all the boys and some of the girls in school had wanted a piece of Natalie, and she discovered quickly that she was delighted to give them some! Unbeknownst to her two elder step-sisters, who themselves had not been shy around sex, Natalie had been fucked by more men by the time she was 18 than Penny and Hannah had by now. Combined. In addition to that, more than a dozen girls had taught her that she very much enjoyed Sapphic pursuits. But it was only now, as she looked keenly at Penny's profile, that she realised that at least ten of the girls that she'd had sex with had been slim with dark hair. Had she subconsciously been attracted to girls who looked like her step-sisters?

Natalie's hands slipped down to between her own rounded thighs, rubbing and stroking at her own wet cunt. She very much wanted to follow up on what Penny had started, but would that freak out the older girl? Penny had started it, but Natalie didn't just want to gently stroke Penny's tits...she ha altogether darker desires.

Natalie had lost her virginity in a friend's bedroom a month after she was 16. A month after that she'd had her first threesome with two older guys, and after that had been the sort of sexual escalation to terrify any parent on the planet, as Natalie discovered an insatiable craving for new degradations. The threesome led to sex with a teacher, which led to her first spanking, which led to her first caning, which led to her getting a thorough punishing on her chubby bottom every Thursday night, and more often if she could schedule it. She started off making up sexy tales to amuse herself and 'justify' the treatment her arse was getting, but soon realised that there was no need to make things up. Her anal virginity went during a session with six of the rugby team on her 17th birthday (four of them could claim it, if they could remember what order they'd fucked her in), and her first lesbian encounter came a week later. No agency would take her on at her age, so she'd set up as an independent escort girl when she was four months shy of 18, and took to her job like a duck to water, only working Tuesdays and Wednesdays so as not to have so much money that her family became suspicious, and also to allow the cane weals from Thursday to heal.

Her ad claimed that she was open to most requests, and this led her to discover just how dirty she enjoyed being. Three months after her 18th birthday, a client asked her to piss her pants for him. She'd never said no to a client and didn't start here. What she'd not expected was the thrill that peeing her knickers gave her, and this rapidly became a part of her personal life. As with everything else Natalie tried, it wasn't long before the next steps. She first wet herself in public whilst walking home from a few drinks in the local pub, almost coming on the spot as warm rivulets of piss ran down her legs in the middle of the street. And it was the very next day that she filled her panties for the first time, shitting herself in a pair of blue, satin knickers whilst she rubbed herself to a shattering climax.

She'd given up escorting when she moved away to uni, although she planned to go back to it soon (she was also toying with the idea of dancing in clubs) and, in a new city, had yet to replace her old maths teacher's cane every Thursday. And so it was that she was already in a frenzied state of needing a lot of filthy sex when Penny's fingers first stroked her chest. Biting her lower lip, she wondered exactly which needs she could fulfil with her step-sister.

To be continued!