Don't know about that one mate. But there is a story where a mother got transformed into a octopus looking creature and inspiring by her, the daughter turned herself into her dog's cock. The story is called drugs drugs drugs. Probably there is some sequel or something like that.

The author you're asking is blackraven2. Great storyteller. This is the first story you asked about:

Getting Too Close

Sasha and Sally had been sort of together for years, basically since high
school, but their relationship was never getting bored. They always found
something new to entertain themselves together, and tried literally
everything, from bondage, over group orgies, up to and including some scary
practices that involved razorblades and left a couple of scars on rarely seen
in public spots.  Their relationship was trusting enough that it even survived
affairs with a couple of other girls and guys on both sides, virtually
unharmed, both of them knew they could always and anytime rely on the other.
It was deeper than love, love was for short, ecstatic affairs, their bond
seemed to have always been and ever be, whether they lived together or not.
Weirdly they never completely stayed together or married either, maybe because
they searched the thrill, needed new ideas, new things. But still, often
enough they explored them together.

When Sasha found a magic book in an old monastery, that included interesting
spells intended for sexual practices, naturally he came to Sally to show her
his endeavour.

The book was ancient, but somehow seemed to be unaffected by time. It had been
hidden in the crypt of a monastery ruin the universities archeology department
was examining, and looked so new his prof didn't even ask when he put it to
his personal stuff. No way it could have been an artifact.

Its insides bore an introduction to magic, but also example spells, and Sasha
had found a very interesting one. Its description read, clumsily translated,
something like "The dream of a men and slave girl, when having intercourse
with slave girl, is to be as one.  'Angrilus merge' makes his girl and his
member as one. Intense pleasure is created for the wielder. His girl witnesses
great alive pleasure during the whole length of the procedure. The
modification stays for three and wears off after three to four to five
ejaculations. Side effects: Strength of his member and vitality is increased."

The picture next to the spell showed a men with erect penis, but the penis was
a girl, with erect nipples, arching back, ecstasy in her eyes.

Needless to say, Sally didn't need convincing. The procedure required Sasha to
create a substance containing various weird ingredients, including cum of them
both, and a complex but detailedly described procedure to mix. The result was
a slimy translucent sticky gel that did smell of nothing. Both of them naked,
he covered his dick with it, her helping him applying it, much to his delight.
She was as aroused as he was, so she turned around, bent forward and awaited
his touch, gasping as she felt his tip gently touch her nether lips.

He grabbed her hips as he had done many times before, shifted his position to
match, then pulled her down unto himself. She grabbed her own breasts as she
was sitting down into his lap, while he was still sitting on the edge of her
bed. She humped his member slightly, shifting back and forth, feeling a warm,
almost burning, but pleasant sensation within her, not unlike some special
lubrication gels they had used before. He let a slight moan, while she looked
at him over her shoulder telling him. "Well I don't know whether this merge
thing might work or not, but this is definitely fun."

He smiled, not caring about the magic part, just about the sensations, feeling
the slight burning, too, and it turned him on hard. Thrusting into her,
lifting his hip slightly and turning rhythmically, he went away in a frenzy of
bliss. She moaned with every thrust of him, reaching down with her hands,
rubbing her clit, while squeezing her own breast, closing her eyes and arching
as she approached a climax.

They both came at the same time, and while spurting into her, somewhere in the
back of his mind he just worried whether she still took the pill, then all his
worries exploded in a burst of ecstasy. Sally shuddered, arching heavily,
grabbing both her breasts, as a wave of energy erupted from her vagina,
intense as she had never felt before.

When Sally opened her eyes again, still shuddering from the afterglow, her
body felt weird. Somehow her legs movement seemed restricted, and very warm,
and something was stuck to her hip. She was resting on Sasha's warm leg,
wondering how his leg became so big. Then she remembered the merge spell.
Looking down she found out that she was attached to Sasha at the waist. More
exactly she seemed to grow out of Sasha just above the hip. Her skin went
wrinkly around her belly and very baggy and stretched downward, completely
engulfing her legs in a sort of bag. She could move in it, seeing the bulge of
her feet press the skin outwards. She also felt the sensations on his skin
around her, his thighs, and his belly behind him as if it were part of her.

Sasha had his eyes open and looked at Sally in astonishment. He could feel her
body as if it was part of his, her skin, her arms, her breasts. Tiny and
sensitive. He clenched his hip muscles, and Sally twitched a bit, her body
shifted upright slightly. "Hey!" she yelped, feeling a weird jerk beyond her
waist, moving her. She turned towards Sasha, looking into his eyes.  "It
really worked" she whispered.

Sasha approached her with his hand, his fingers suddenly very big, ever so
gently touching her breasts and exposed nipples. She smiled, but he gasped
from the sensation. Sally realised. "You can feel my body?" It made sense, if
she could feel his skin around her he would probably sense all of her.

Sally smiled evilly, touching her skin with her hands, rubbing her sides up
and down, then squeezing her breasts, continuing with her neck, then her
mouth, extending her tongue, licking her arms. Immediately she felt a pulsing
jerk in her hips again as Sasha responded to the stimulation, lifting her
pointing straight up. He couldn't help but grasp her whole body with his hand,
feeling her breasts between his fingers, feeling his fingers on her breasts,
the slight touch so sensitive.  Sally felt a pulsing sensation in her belly,
and a warmness spreading, filling her, turning her on like crazy. She squeezed
herself into Sasha's hand, rubbing herself against his fingers, moaning.  He
moaned, too, tightening his grip slightly and stoking her, almost as if giving
himself a hand job. With the new unique sensations it took not long, then he
came hard. She had an orgasm at the very same time, arching strong, grabbing
her breasts between his fingers, her legs clenching together, squeezing the
testicles beyond her feet. Then she felt a pressure, as something squirted
inside her, through her. Her head arching back, and a warm liquid pressing up
through her throat. His cum exited her mouth in a long arch, tasting slightly
salty on her lips.

Sally didn't care, the afterglow being more intense then the last time. She
felt a nice warmness all inside her. While the pulsing had receded mostly, she
rested relaxingly in his lap. Gently she kissed his legs, feeling Sasha's
fingers on her back, where he stroked her, petting her nicely. "That was
great" she said. "It felt so, complete." Sasha just nodded, still dizzy from
what he had experienced.

"How do we get apart again?" Sally asked after a while. Sasha reminding her
about the three to five ejaculation note in the book. Sally smiled viciously.
"You know, we could call Marita over for a threesome, while this lasts then."

Sasha thought about it and smiled, then stood up, to get the phone. Sally was
lifted from her resting place in his lap and dangled head down from between
his legs. "Hey!" she yelped, shifting back, arching backwards to get into an
upright position.  Somehow, when he was not excited, their joint seemed to
have much less strength, she wasn't able to hold up, just arching to a sort of
straight forward position. So she grabbed his hair and pulled herself up that
way.  "Ouch, hey, don't pull that." "Sorry, but I prefer not dangling between
your legs like that, it makes me dizzy." More carefully he walked on to the
phone and pressed one of the quick dial buttons. He had had a short affair
with Marita, but they didn't get along too well. No one did in the long run so
Marita was still single, but they kept on good terms and occasionally had some
fun. She didn't object: "Yeah, sure, why not. Was fun last time. But I have
something in the oven here, I can't come over tonight.  Why don't you come
here instead?" Sasha glanced at Sally, she thought about it, then nodded.
"OK, lets do it like that then, we'll be there in 10 minutes.

Sasha got his boxer shorts, and started sliding in. Carefully he pulled it
over Sally, she grabbing the fabric and aiding it over her head. She found out
it had a comfortable bulge in it where she could rest, while he walked and got
the rest of his clothes on. "Are you OK in there" Sasha asked? Her response
was muffled, but he could feel that she had nodded. It was still weird to feel
her body like this, as part of his own.

Walking over, he felt her shifting in his pants, and again it aroused him. Her
skin seeming so much more sensitive. She felt the arousing pulse from beneath,
shifting her around, erecting her position a bit. A slight moan escaped her,
as her now erect nipples brushed against the skin of his pants.  She yelled at
him. "Hey, don't tell me you feel like this every time you walk." Sasha
smiled, then grabbed the bulge in his pants and squeezed a bit, feeling the
pressure on his Sally, forcing a slight Moan out of her again.

Marita was surprised, when Sasha seemingly came alone. It took a little bit
convincing of him to talk her into starting without Sally, as she would "come
later". Sally had a really hard time not to giggle to loudly.

Finally they made it to Marita's bedroom, Sasha getting hard as he hugged
Marita and gave her a little kiss. Sally found it weird to feel the pulsing
feeling beneath her waist, and getting all horny without an apparent reason.
But she enjoyed it nonetheless, eagerly awaiting Sasha to drop his pants.

Sasha told Marita he had a surprise for her. She seemed to expect a new
piercing in an interesting spot or something, which was close enough. Sasha
undressed in a teasing way, showing his butt to Marita, careful not to let
her see Sally yet. Sally was fully upright, glancing up at Sasha with lust in
her eyes. "Shall we show her?" she whispered. He just nodded with a smile,
then turned around.

Sally posed, proudly, with her hands behind her head, and her chest outward.
"Tadaa!"

Marita didn't believe her eyes. "How did you get there?" She approached to have
a closer look. Sasha gasped as Marita touched Sally, checking if she was real.
both Sasha and Sally slightly shuddering at the sensation.

Sasha gave a brief explanation, leaving Marita with anticipation. "So you guys
want to have sex like that? Wow, that's bold." She posed on the bed, her legs
spread, showing the pink slit between her legs, her hair down there all waxed
away.

Sasha crawled over her, Sally between his legs approaching Marita's pink
softness. Then he slowly lowered himself, placing Sally's belly across
Marita's vagina. It looked really huge to Sally and was so nicely soft. She
grabbed the metal ring, Marita had pierced through her clit with both hands,
and pulled slightly. Sasha felt the cold metal against Sally's hands as he
caressed Marita's breasts. Shuddering even more as Sally bent forward and gave
the cold metal a lick. He could even feel Sally's tongue.  Sally didn't stop
there. She pulled the ring further, then licked Marita's clit, taking it into
her mouth, sucking on it. Marita moaned.

Then Sasha pulled his hip back a bit, lifting Sally up. But she kept holding
Marita's ring with both hands, then stuck one hand into the increasingly
liquid moistness further down between Marita's labia.  Sasha lowered her
again, and Sally's breasts touched against Marita's wet lips. Sally inserted
both arms into Marita, opening her before her head, like a diver.

Sasha thrust forward. Sally entered Marita up to her shoulders, only her
breasts pressing against Marita's labia for a second, the touch on her erect
nipples sending shivers through her and Sasha. Marita gasped, arching as Sally
penetrates her, sliding further in, her hard nipples and her hair rubbing the
insides of her vaginal entrance.

Sally entered a moist warm tunnel, her whole body pulsing with pleasure. She
stretched her arms against the soft skin around her, caressing the slicky
insides of Marita. The smell was intense, but not too bad. She had licked
Marita's pussy before, but never had she been that close.

Sasha thrust her fully in, inserting her up to the waist, pressing his
hipbone against Marita's metal ring armored clit. Then, panting for a few
seconds, he slowly pulled her out a few inches.

Sally shuddered as her breasts slid over the slightly ripply inside of Marita
again, her fingers caressing the tunnel walls in front of her. She felt a
familiar taste on her tongue as a few drops of precum fond their way through
her body and up her throat. Hastily she  gulped them back down.

Then it went in again, and again. She heard Marita moaning, the walls around
her contracting in uncontrolled spasms. And finally she couldn't hold back
anymore, arching, shuddering, spurting a big load of white substance from deep
within her deep into Marita.

As the pulsing dizziness cleared and she opened her eyes, she was still inside
Marita, but again more relaxed. Marita's inside still contracted, sucking at
her, pulsing. Then slowly she felt herself pulled out as Sasha, who was
panting heavily, got her free.

Blinking the stickiness of her eyes she could get a glance at Marita, slick
liquid oozing out between her legs, staining the blankets. Marita was
clenching her hand into the pillows, the other on her breast, her hip
occasionally twitching, her eyes still closed.

As she finally opened her mouth again, she seemed to be glowing with deep
happiness from within. "Wow! Just Wow!"

Sasha looked at Sally, both of them similarly happy with what they did,
Sally's hair clinging against her body, all covered with sexy juices.

"We need to get you clean though." Sasha suggested. Sally nodded, gulping down
a last drop of cum, as they went to the bathroom.

Sasha went under the shower, and put Sally under the sprinkler, then offered
some soap to her. Then he just enjoyed as she brushed her own body, sending
shivering sensations through his body again, as she touched herself.

When Marita was done cleaning herself too, they went to the living room, still
naked as they were, to eat something.

"So how do you get back to normal then?" Marita asked Sally.  "Its supposed to
wear off after three times cumming it said. This was the second." "Just like
that? Poof and you are back to normal?" "I don't know" Sally said. "It
started just like that, so why not. What did the book say?" Sally asked Sasha.
Sasha shrugged. "I don't know, it just says it will go back to normal after 3
to 5 times or something." "Fair enough. I assume you didn't do that before,
did you?" Sally and Sasha shook their heads.

Later, Marita offered them food, and while Sasha enjoyed the delicious meal,
Sally found out that she was unable to eat anything, without hurting both
herself and Sasha. Her insides didn't seem to work the same way anymore.

So instead they went dressed again, Sally snuggled into Sasha's warm
underpants, and they left for home.

"I'm tired, can you get me back to normal, before we head to sleep?" Sally
asked him after they arrived. Sasha smiled, considering the procedure that
implied. "Sure, just make me cum." Sally gave him a mischievous look, then took
one of her nipples between her fingers and twisted it till it hurt.
Immediately she felt a jerking in her lower body, as Sasha responded, letting
out a gasp. A slight pulsing started and Sally was heaved into a more upright
position again. It came naturally to her to start rubbing herself, teasing
herself.  The throbbing went stronger. She could feel Sasha's heartbeat all
over her body, as if he pumped her with his blood. That somehow turned her on
even more. She caressed her own neck, then Sasha's strong hand engulfed her
whole body and started to stroke slightly.  She closed her eyes, feeling a few
drops of precum coming up her throat again, filling her mouth with the thick
tasty slime. Then a surge deep within her made her arch, like an electric
shock, and spurt a big load of cum out of her mouth, and across the bedsheets.

As she came to herself this time, she felt weak and limp. Somehow something
was odd. She realised she couldn't feel her legs. She could however perfectly
feel Sasha's testicles in the sack beneath her.  Something in her lower torso
seemed to have changed too, her muscles felt different, and her lower spine
seemed to be simply gone.

Her upper body, breasts, shoulders and arms seemed mostly as before. Still it
was odd.

Sasha felt it too, and looked at her. Then felt his ball sack with his hand,
lifting Sally up, who's body was bendable in weird ways.

"You didn't get loose yet." he thought load.

"I think, somethings wrong. It feels like I'm turning into your dick or
something."

Sasha looked more closely, squeezing Sally's waist. There seemed to be no bone
in there. But his body responded to the touch, and soon Sally felt a light
throbbing again, making her belly elongate, thicken and harden, a few veins
appearing under her skin that weren't there before.

Sasha gazed at her with worry and fascination at the same time. It felt like
getting a boner, but instead Sally went erect. Soon the swelling reached her
chest, and, making Sally gasp, heaved her chest up, almost against her will,
as if she had his dick between her rips.

Sally looked at him sadly, she didn't like this new development. Still of
course her body responded to the sensations, her nipples growing hard and
pointy, but her arms stuck sideways a bit helplessly. She tried to speak, but
couldn't flex her lungs enough, only a soft moan escaping her lips.

Sasha panted, then waited for the erection to ebb down. Slowly Sally relaxed,
being able to breathe again. "I think something is wrong, can you check your
book again? Maybe you oversaw something."

He nodded and walked over, Sally dangling helplessly from his waist. Then came
back sitting down. He placed the book in his lap under Sally so she could look
at the pages too, and read the spell description again. But it clearly said it
would wear off after 3 to 5 times. "Well we had three times, maybe try once
more. Ready?" Sally nodded and braced herself, then Sasha started stroking his
dick, her body, until the throbbing had filled her up that she thought she'd
burst, throbbing with every heartbeat of him, making her dizzy but also
turning her on like crazy. Soon again she couldn't hold herself. She felt his
warm load press up through her body, through a pipe somewhere under her skin,
ending in her mouth making her squirt his cum over the sheets again.

As the afterglow ebbed down, her hair had disappeared, leaving her head skin
bare and soft, her face elongated and thick, her tongue seemingly gone, but
her mouth being weirdly round now. Within it she could still feel some drops
of cum, but she couldn't gulp. She couldn't turn her head either, but there
seemed to be a lot of skin around her shoulders. Sasha lifted her up. and
looked at her. Her arms were gone too, and her breasts were only slight bulges
on the front side of his dick, ending in visible nipples.

Sally tried to speak, but she only got a moan. She seemed to have no bones in
her chest anymore, her movement restricted to twitching and slightly bending
one way or the other. Her lower body was completely limp and looked exactly
like Sasha's dick would normally look.

"This isn't right." He said. "There must be a mistake, I think this wearing
off doesn't mean you get free, you are just turning into my dick. We need to
find a counter spell or something". Sally managed something like a nod. Not
much but at least proofing to Sasha that she was still there.

The page with the spell didn't give any more clues, so he flipped a couple of
pages back. Other spells, most titled Angrilus something. Many of them sexual
practices, most of them very cruel to the girl. Deciphering a few he came to
the conclusion that whoever that Angrilus were, used his slave girls to
strengthen his own vitality to grow incredible old. He also had had sadistic
tendencies.

Finally, at the beginning of what could be a chapter he found a sort of
introduction. It told what he had expected. Angrilus was a sadistic bastard,
and each and every spell he used lead to the death of another innocent girl.
The spell they did seemed to be a sexually fantasised modification of a spell
that simply absorbed another living beings life energy into oneself. He
translated loud what he found, and he felt Sally shudder and sob.  Frantically
he searched the book for possible clues to how to counter the effect. Sally
eventually sleeping on his lap, he spent most of the night making notes,
learning more about the magic. But eventually he was too tired to think,
placed the book away and went to sleep, careful not to wake Sally while
covering himself with a blanket.

Sally woke up in the middle of the night. It was warm, dark and moist, some
skin covering most of her face. Her lips brushed against fabric, her sides
resting against Sasha's warm tights. She could hear him snoring slightly.

She tried to stretch herself to get her eyes free. Wiggling a bit she felt
herself sliding over his legs, the fabric brushing against her tip.  Wiggling
more, eventually her body responded. Or was it Sasha's? She couldn't tell. But
with a slight pulsing she felt herself get erect a bit, the skin pulling back,
freeing her eyes. Soft fabric brushed over her exposed face.  Nothing to do,
imprisoned under the twilight of the blanket she started thinking about her
situation. Being in place of Sasha's dick wasn't even that bad, she found. She
always had liked to be really close to him. But the recent merging, turning
her limp and immobile was depressing. And another cum would turn her completely
into his dick, unknown whether she'd even still be able to think. But then she
thought about him, having doomed her, while caring for her. He'd probably
spent the rest of their lives trying desperately not to cum ever again. And
eventually it was inevitable, a moist dream or another girl screwing with him,
and that would be it. She wasn't really looking forward to him having to pee
either. She could feel his bladder somewhere behind her, it was starting to
strain, he would have to pee in the morning.

She couldn't sleep, so she continued pondering. But as the time went on, a
decision was slowly forming in her mind. It made no sense to try to postpone
the inevitable. It might be better for her and better for him to get it over
with.  When he stirred again, then turned around in his sleep, squeezing Sally
between his hip and the bed, pressing her into the sheets, it settled her
decision.

Sally started to wiggle a bit, trying to press herself into the sheets a bit
more.  Eventually Sasha's erection grew, elongating her, exposing her face
fully.  Veins bulged on her body, giving her a ripply look, her breasts
shifting over the sheet. She gasped slightly, then with tears of
determination, she continued rubbing over the sheets.

Sasha didn't wake up. But he still responded, letting a couple of
unintelligible moans, and starting to hump the sheets rhythmically. By that
Sally didn't care anymore, sexual bliss taking over logical thinking. She felt
the pulsing of Sasha's blood in tune with his heartbeat pump up her body
completely, even her face hard and erect, her skin  smooth and firm, stretched
over the swelling within her. She couldn't even move, as firm as she was
pressed into her skin, she felt the pipe going through her, ending in her
mouth. And she had no way to stop the liquid of the first precum sipping out
and wetting the sheets, sticky on her cheeks. Her breasts started hurting
slightly from rubbing against the sheet so much, but she didn't care.
Shuddering she awaited the climax, at the same time hoping it would take a bit
longer, since it would be her end, and also because it felt so good, so
good...

Sasha spread a big load of cum into the bed sheet, but he was so tired, he
didn't even wake from it. It wasn't until in the morning, when he looked at
his surroundings, and, seeing Sally's bedroom and the magic book on the table,
it dawned to him what had happened. He hurried to put the sheet away to see
after Sally, but the nagging feeling that she wouldn't be there, judging by a
slight stickiness and him unable to feel her, turned to reality when he saw
the yellowish stain on the sheet, and his own cock, limp and small and wrinkly
between his legs, and no trace of Sally anywhere.

He cried. He tore on his hairs, ripped the sheet of the bed and kicked them
through the flat, but it didn't change anything. Sally was gone. No not
really. She was part of him now, he felt younger, healthier, and his dick
seemed bigger, even while it was limp. And it hadn't been small before.

But somehow all of that wasn't what he urged for...

Yay!