As Katrina quietly tip-toed along the hallway she could
hear the gentle tick-tock of the old grandfather clock
that stood at the end of the corridor. Street lights
shone in though the open bathroom door, providing her
with a dim view of where she was going. Her feet made
barely any sound on the soft carpeted floor, so when
she heard a muffled bang, she stopped. Standing still
like a rabbit caught in the headlights, she listened
for any more noises.

Suddenly it clicked into place in her mind; it was just
the plumbing, as the house settled for the night.
Almost laughing at herself, she quickly made her way to
the small alcove at the head of the stairs, where a
bedroom door lay open. Concealing herself in shadows
she hid behind the bookshelf next to the door. Looking
through the doorway, she saw her older sister Lisa
lying still in her bed.

As she looked in on her sister, Katrina reflected again
just how different they were. She was only thirteen,
and unlike Lisa she aspired to be good. She went to
church regularly and never wore revealing clothes
despite the fact her young body had blossomed early on
into a pleasing shape.

With her long legs, narrow hips and firm B cup breasts,
she was vaguely aware that boys liked to look at her.
But she didn’t care much for boys; they never
understood her desire to behave. The few boys who had
been bold enough to try and feel her breasts through
her high collared, loose fitting shirts had quickly
been aquatinted with a firm smack across the face. They
never tried again.

Sixteen year old Lisa had dark brown hair and
mischievous green eyes that always hinted at ideas of
misbehaving, a polar opposite of Katrina’s smooth
blonde hair and innocent blue eyes. Her figure was
similar, but her hips were bigger and her breasts were
a fuller C cup. She rebelled against all constraints
put on her, and seemed to enjoy teasing boys by
flaunting her curves.

Katrina felt a guilty feeling stir inside her once
again as she stared at her sister, willing her to do
something. For quite some time now she had been
watching her sister at night, after accidentally
hearing her moaning softly one night and sneaking past
her room to see her touching herself. After watching
her a couple more times, Katrina knew what her sister
was doing: masturbating. Something she had been told at
church was a sin. But how could something bad arouse
such pleasant feelings in her, she wondered. She
enjoyed the warm, slippery feeling between her legs
each time she watched Lisa, though she never touched
herself in the same way.

Just then, Lisa began to stir. Katrina watched eagerly
as Lisa threw her blankets off and reached down,
pinching her nipples with one hand and rubbing between
her legs in a circular motion with one finger. As she
always did, Katrina thought how wonderful it was that
Lisa always slept naked.

Tonight Lisa quickly started moaning and wriggling
around, evidently enjoying every second of her own
touch. It wasn’t long before she climaxed, letting out
a muffled cross between a moan and a sigh. Katrina knew
sometimes it took her sister a while, whereas sometimes
she finished quickly. She was always disappointed on
these quick nights but as she silently made her way
back to her own room, she reminded herself of a
comforting thought. There’s always tomorrow night.

***

The next night, Katrina tried to stay away from her
sister’s room. She had started feeling that she was
spending too much time hovering around her sister’s
door, and decided she should try to cut back a little.
The guilty feelings every time she concealed herself
behind the bookcase were starting to bother her. But as
she listened to the sounds of her sister getting into
bed, she knew she wouldn’t be able to stay away.

Waiting for a few minutes as her parents finished
locking up the house and turning lights off, she
eventually crept out of bed and hurried down the hall.
Taking up her position behind the bookcase, she noticed
King, the family Rottweiler, laying on the floor at the
foot of Lisa’s bed. Katrina was slightly bothered. She
knew King sometimes slept in Lisa’s room, but he had
never been there before when she spied on her sister.
Hoping he wouldn’t notice her and come over to
investigate, thus giving her away, Katrina stared hard
at Lisa.

Lisa gently eased her blankets off her, her hands going
straight between her legs. As Katrina watched her
fingers pinch and stroke, she heard Lisa mumbling to
herself.

‘Oh my God, I’m so wet tonight. Does my pussy ever need
some attention… if only I had someone here to give me
a good cunt-licking!’

Surprised, Katrina turned Lisa’s words over in her
mind. Was pussy what her sister called the space
between her legs? And what about the other word, cunt?
Was it just another word for the same thing? And the
licking… did it actually feel nice to be licked down
there?

Then Lisa did something that surprised Katrina. She sat
up and swung her legs off the bed, sitting on the very
edge of her mattress. She then spread her legs wide,
treating Katrina to a shadowy view of her most private
place. Then she lightly slapped the inside of her thigh
and whispered to the dog.

King sat up immediately, and when he saw the way his
mistress was sitting he made his way to her as if he
had done it many times before and knew what was
expected of him. Angling for a better look, Katrina
nearly fell over with shock as she saw King lick her
sister between the legs!

Lisa threw her head back and moaned softly, pulling the
dogs head closer against her with one hand. ‘Oh yes
King, lick my wet little pussy. Get it right in
there… ohhhh yes, tongue my clit you good dog!’

This seemed very wrong to Katrina. Never had she ever
heard of anything like this before, she knew it had to
be very very wrong! And yet… the feelings that came
between her legs whenever she watched Lisa were
stronger than before. For the first time ever, she
slipped her own finger inside her panties and felt the
folds between her legs.

Immediately she noticed the wetness that her sister had
been talking about, the private place between her legs
was absolutely soaked. Experimentally she rubbed her
finger along her slit, finding a hard little knob. She
rubbed at it and felt an incredible pleasure flood
through her, almost making her cry out. She continued
to rub as she watched King lick Lisa, Lisa’s eyes
closed as she continued to moan softly.

All too soon Katrina began to hear the noises that
meant Lisa was almost finished. Disappointed, she
watched Lisa let out her last moan, her entire body
shaking. As her body stopped quivering she pulled the
dog up against herself on the bed, allowing him to lick
her face and even putting out her own tongue to kiss
him. Katrina quickly made her way back to bed, her mind
reeling.

***

The next morning, their parents had some news. Over
breakfast they told the girls they were going away for
a business trip, and would be gone overnight.

‘Now it’s just a quick routine matter,’ their mother
said, rummaging through her bag and locating a list of
telephone numbers. ‘We’ll be back early tomorrow
afternoon, I’m sure you can both make your own
entertainment until then. Lisa, look after your sister
and for Christ’s sakes be good. Don’t forget to feed
the dog, keep him in the house during the night if it
makes you feel safer. Your father has his mobile phone
but if he doesn’t answer, try these.’

‘Don’t worry,’ Lisa said innocently. ‘We’ll be fine,
right Katie?’

Katrina nodded mutely, surprised that her sister was
being nice to her. Usually she snapped and argued
whenever she had to babysit her. Before she had time to
worry about Lisa’s change in behaviour, their parents
were gone and they had the house to themselves. Lisa
disappeared upstairs to chat with her friends online,
and Katrina decided to make some cookies.

For the rest of the day they both pottered around at
their own various amusements, and for dinner Lisa
ordered a pizza. They watched a scary movie, which Lisa
let Katrina stay up to see the end of. Again it was
sufficiently unusual behaviour for Katrina’s guard to
be up. Finally after the movie, Lisa declared it was
time for bed. But the younger girl had been slightly
spooked by the movie, and seemed reluctant to go to her
bed alone. Apparently not in the mood for arguing, Lisa
told Katrina she could sleep with her.

Katrina anxiously changed into her long sleeved, high
necked nightgown which fell below her knees, wondering
what Lisa would wear to bed. She was relieved yet oddly
disappointed to find Lisa wasn’t naked when she made
her way to her room, but wearing a tiny pair of shorts
and a t-shirt that looked a size too small for her.

‘I’ve locked up,’ Lisa said. ‘And we’ll keep King in
here so you feel safe okay? Now, get in the bed and go
to sleep.’

As Katrina tried to get comfortable, she felt Lisa
snuggle in behind her and throw her arm around her
waist, pulling her closer.

‘What are you doing?’ Katrina asked, surprised.

‘Hopefully stopping you from feeling like such a wuss,’
Lisa replied.

Katrina accepted this reply, but felt a strange feeling
wash over her as Lisa ran her hand up and down her
thigh, slowly pulling her nightgown up above her knees.
When the hem was halfway up her thighs however, Katrina
felt she’d better say something.

‘Lisa, why are you pulling my nightgown up?’

Her sister didn’t reply, and Katrina was about to ask
again, when she felt Lisa’s hands grip tightly onto
her. In a quick move, Lisa had rolled Katrina onto her
back and was sitting astride her with her hands
clamping her wrists to the bed.

‘Lisa?’ Katrina asked, feeling slightly scared.

‘I know you’ve been watching me late at night,’ Lisa
said, staring hard at her squirming sister. ‘Watching
me touch myself, you’re such a little pervert spying on
me like that. What do you think Father Crimmond would
have to say about that?’

Shocked, Katrina felt her insides freeze. ‘I… I…’

‘Did you like what you saw? You’re not such an innocent
little church girl as you like everyone to believe are
you?’ Lisa started rubbing her crotch against her
sister. ‘I bet you touched yourself when you watched
me. Did you know your church says that’s a SIN!?’

‘Please Lisa,’ Katrina struggled. ‘Let me go back to my
own bed, I promise I’ll never spy on you again!’

‘No, I don’t think I will.’ Lisa shrugged. ‘You know,
it’s not as fun to play with yourself when you’re
alone, it’s better when there’s someone else there.’

Seeing where her sister’s train of thought was headed,
Katrina fought to get free. ‘No Lisa, it’s not right.
We’re sisters!’

‘You’ll enjoy yourself,’ Lisa smirked, quickly letting
go of one of Katrina’s hands and reaching for something
that was wedged in the gap between the bed and the
wall. As she handcuffed Katrina’s wrists to the
headboard, Katrina realised her sister must have been
planning to make her into her plaything all along. She
opened her mouth again but Lisa slapped her firmly,
stinging her cheek. ‘If you make any noise other than a
moan of pleasure I will hit you again. Understand?’

Katrina nodded firmly, a single tear running down her
cheek. Lisa smiled with satisfaction, and produced a
pair of scissors which she used to cut away Katrina’s
nightgown.

The young girl finally lay naked, and Lisa leaned
forward and kissed her gently on the mouth. Then she
probed at her closed lips with her tongue until Katrina
finally opened her mouth and, feeling she had better
cooperate, starting passionately kissing her sister
back. Lisa then kissed down her neck and all over her
breasts, gently biting her nipples.

It was a pleasurable feeling, and Katrina felt a sweet
spasm between her legs. Dismayed she hoped Lisa hadn’t
notice, and she would stop soon. But Lisa was still
kissing her way down her sister’s body until she
finally came to her light bush of pubic hair, where
Katrina’s legs were closed tight. With a firm and
persuasive hand, Lisa pulled her legs apart.

‘Mmm… virgin pussy,’ she said, eyeing Katrina. She
then lowered her head and started lightly tonguing
along her slit, occasionally pushing her tongue inside
Katrina’s tight little cunt. She then lightly flicked
her tongue over her slit, causing Katrina to gasp in
pleasure.

‘Oh, so you do like it?’ Lisa asked, her eyebrow
arched. ‘You like me licking your tight little virgin
cunt?’

As she spoke she pushed her thumb halfway into her
sister’s hole, feeling the resistance of her hymen
blocking her from going further. Seeing her sister try
to hide the pleasure that was evident on her face, Lisa
once more lowered her head and started stroking circles
around her clit with her tongue. Once her face was
covered in Katrina’s juices, Lisa came up to her
sister’s face.

‘Do you want to taste your pussy juices?’ she asked.
Katrina hesitated, then shook her head. Ignoring her
refusal, Lisa firmly kissed her sister, exploring her
tongue with her mouth. When she realised her sister was
eagerly kissing her in return, she stopped and
repositioned herself so that she was able to quickly
whip off her t-shirt and shorts. She then placed her
own dripping wet pussy above Katrina’s face.

‘Lick my cunt, like I just did to yours. Now!’

Almost experimentally, Katrina stuck out her tongue and
lightly stroked Lisa’s clit. Lisa moaned loudly,
pressing herself down harder against her sister’s face.

‘Lick me harder and faster you little slut,’ she
groaned. ‘Lick me just like I did to you.’

Katrina obeyed and quickly proved to have quite an
untapped talent. As Lisa wriggled around on top of her
sister’s face, Katrina eagerly lapped up her juices
until Lisa was on the verge of cumming. She moved away,
knowing the best was yet to come. After first
extracting a promise from her dazed sister not to run
away, Lisa unlocked the handcuffs.

‘Now,’ she instructed. ‘Kneel on all fours on the floor
beside the bed and lick me again.’

Doing as she was told, Katrina was quite caught up in a
frenzy of clit-tonguing when King smelt the arousal in
the air. He got up and saw Katrina in an ideal
position, then quickly started to run his tongue all
over her exposed twat. Katrina turned in shock when she
realised what was going on, but Lisa grabbed her head
back and held her firmly between her legs again.
Disgusted with herself but unstoppably turned on,
Katrina kept licking Lisa while King slid his tongue as
far inside her pussy as he could.

With her face buried in her sister’s cunt Katrina’s
moans were muffled, but it was enough for Lisa to start
approaching the best climax of her life. Watching her
perfect, saintly, church going sister being eaten out
by a dog as she eagerly licked up her older sister’s
juices was such a deliciously forbidden sight.

Encouraged by her sister’s moans she started crying out
in pleasure herself, when something caught her
attention. King was moving around and without warning
he suddenly mounted Katrina. The younger girl stopped
licking at once as King thrust at her with his erect
cock, and looked up.

‘Lisa, what’s he doing?’

Unable to believe her eyes, Lisa watched enviously. She
had planned to one day have sex with King if the
pleasure of his tongue wasn’t enough, but now he was
going to take her little sister’s virginity! ‘He’s
going to fuck you Katrina, he’s going to put his dick
inside you and turn you into his bitch!’

Katrina’s eyes opened wide with shock as she tried to
move away. But Lisa wasn’t about to miss the best
possible sexual scene of her entire life. She grabbed
Katrina and forced her head between her legs again,
gasping as she felt that smooth little tongue stroke
her clit once more.

King finally made contact, thrusting his hard rod into
Katrina and causing her to scream out. Lisa watched
eagerly as King thrust at the younger girl and Katrina
started to move in rhythm with him. In fact, she had
even started licking at Lisa again and was moaning
loudly with horny desire as King slammed into her
harder and harder. Unable to stop herself Lisa threw
her head back and screamed as her orgasm ripped through
her, hearing a similar scream echo from her sister as
Katrina experienced her first orgasm.

King also appeared to cum quickly, only several minutes
after he had first started licking Katrina he was
withdrawing from her and causing a river of dog cum to
gush from her stretched hole. Katrina fell to the floor
in a heap, whimpering as the aftershocks of her orgasm
spread through her. Lisa lay on her bed, looking down
at her little sister. Finally Katrina had gathered
enough breath to speak.

‘I don’t think I’ll be able to go to church again.’

Lisa smiled. ‘Of course you won’t. Sinning is much more
fun.