Rose laid the Doctor's book down on her bed and frowned. It really wasn't much of a help. She'd gotten more questions than answers from the text. Was she going to develop a Time Sense? How exactly did the respiratory bi-pass work – how in the universes could it be "semi-voluntary," anyway? Exactly why did Gallifreyans have hair on their heads and no where else? What was the evolutionary point? And really, she thought shaking her head, there wasn't a bit of useful information on how to seduce a Time Lord or what exactly would happen if you managed it.

Rose eyed the book suspiciously and nudged it with her toe. What use was a biology book that had only three pages on reproduction? Three pages! Granted, humans were sex obsessed, but this was going a little overboard on the whole "higher species" thing. There'd been a nice long chapter on those Looms the Doctor had talked about – details on the genetic sampling, the computer program for mate selection, the process of speed aging and a small note about incorporation of "lesser species" into the Looms to "indulge the wayward among us." But only three pages on the actual biological and natural reproductive impulses of the species.

Rose flopped backward on her bed, nearly hitting her head on the headboard. Three pages. She'd read them first, nearly a week ago, when the Doctor had first given her the heavy tome. She'd figured there was more, never dreamed she'd finish the whole bloody book and still not understand what was happening. She'd managed to piece together only a sketchy outline of what was really going on, and that was more from watching the Doctor than from reading those three bloody pages.

Observation One: The food fetish the Doctor had introduced Rose to was only the tip of the iceberg. The book quite clearly spelled out that part. The Gallifreyan tongue was able to catalog information at a molecular level, even so far as sub-atomic in some individuals. This, Rose had finally managed to figure out after hours of digging in the fine print, was some sort of mating safe guard. Since Gallifreyans regenerated they couldn't be sure exactly who anyone was. Historically, this had created a little problem. One did not want to end up accidentally mating with one's parent or sibling or offspring... So they had adapted the ability to do on the spot genetic testing to make sure inbreeding did not take place. Eventually, over time, this sense had evolved to include more information, such as general health, hormone levels, family background. All sorts of personal information was coded into the DNA and could be read by a special decoder tongue swipe.

When the Looms were invented this little evolutionary development was abandoned and the only "modern" repercussion was the grey mush the Doctor had mentioned as the main food consumed on the planet. The Doctor, however, had resurrected it, taking the ability to a new level and figuring out that it was good for on the fly substance analysis of just about anything, from oil on walls to blood samples. No matter how you looked at it, the Doctor was weird by human and Gallifreyan standards. Only the Doctor would take a sexual function and use it to do forensics.

Rose groaned and hid her face behind her hands. The book made it sound very clinical. One lick to find out all sorts of nifty information. Reading between the lines Rose had quickly figured out that this wasn't something people did in public. She'd known that when she'd cheekily confronted the Doctor in the console room. So, as far as Observation One was concerned, she and the Doctor had already done something intimate. How intimate Rose wasn't quite sure, but the Doctor seemed to be very embarrassed by it and somewhat ashamed. It reminded her strongly of her first experience with a boy's hand down her bra. He'd been shocked and terrified seconds later, unsure what to do. He'd jumped off her mother's couch and been out the door ten seconds later. He never did talk to her again at school – he could only stammer and blush. Rose had been mortified at the time, but in hindsight it was hilarious. The Doctor was behaving only slightly better.

Observation Two:

Equipment wise, things appeared to be pretty much the same for both species. Rose had carefully looked at the anatomical drawings and couldn't really see much of a difference. There was a vague mention of some sort of "prong" that was to "increase the likelihood of conception in the pre-historic Gallifreyan." Rose wasn't quite sure if that was a euphemism for the actual male organ or something else. They hadn't thought to include detailed drawings of either gender's more private parts, considering them "obsolete". Having undressed an injured Doctor more than once, Rose was pretty sure he was close to bog standard down there, but she wasn't exactly happy not to have confirmation.

Observation Three:

Her body wasn't the same and not about to respond as she remembered.

The last one was the deal breaker for Rose. She wasn't a stranger to attraction. She'd never been a prude herself, if not quite up to Jack's standards of open mindedness and flexibility. Only thing was, new Rose didn't seem to have the same set of rules and without them she wasn't sure what to do or what she even wanted.

She'd tried a little self exploration pretty quickly after the change. Rose didn't want to have any surprises in that category later on. She felt pretty much the same, all the same external parts and all. Only, no matter what she never got aroused. It was quite frustrating. Not even a little quiver, not with her favorite smutty romance books, her trusty cuddle pillow, or even her little battery operated friends.

The book wasn't any help. Seems Gallifreyans didn't condone self amusement, no surprise there. The Doctor's blushing commentary the week before and his confession to being a near virgin made it clear. His people were very, very prudish. Evidently they were also either incapable of arousal as she knew it or incapable of doing it alone. The book clearly stated that the female body secreted a substance that allowed for painless penetration. Theatrically, Rose mused, nothing should have changed. Only it plainly had.

For a while Rose thought she might be broken. Then, they'd visited a planet in the middle of a rainstorm. One glimpse of a drenching wet Doctor looking like a drowned puppy and her chest had tightened and she'd had to force herself not to make that purring sound. When she'd gotten back to her room her knickers were soaked, and not from the rain.

Rose had then started to catalogue her physical reactions. Old vs. new. She'd even gone so far as to make a nice neat little chart.

It had been a while since Rose had actively contemplated her body's response to lust, but she remembered what the Doctor use to inspire in her. Her heart would start to flutter and her breath would hitch. She'd catch a glimpse of him or a hint of his scent and that night she'd lie in her bed and think about what it would be like to have him next to her, just touching her skin – nothing sexual, she'd been afraid to even dream it. And she'd ache.

Some nights the dull throbbing in her center was so bad she'd whimper and bite her lip to try and stay quiet. She'd been sure on those long lonely nights that if he'd so much as peeked in on her she'd have died or raped him – no other options would have been possible. Her head would spin and tears would come to her eyes. She'd arch into the empty spaces around her, her hands fisting in the sheets not daring to even touch herself – needing him so badly it felt like she might die. She felt so empty, like an endless echo of herself and she needed him inside her. It was physical.

That was the old reaction. The new, the new wasn't something she understood. It still hurt. It still ached. She still felt empty. Only it wasn't physical. Her nipples still hardened and her hearts now clenched in an odd syncopation. Her respiratory bi-pass would tense and she'd let out that embarrassing purr, but that was it. The ache wasn't in her body. It was in her mind.

Rose found herself wanting desperately to reach out to him, to touch him in a fashion she knew, without those three unhelpful pages, was more intimate than human sex. Instinctively she knew that what she was aching for, what the Doctor seemed to know was inevitable, wasn't something to do lightly. The Doctor said that mental contact made them horny. That wasn't the truth – not exactly, at least not for Rose. Lack of mental contact was driving Rose insane, the absence making her hyper sensitive and perpetually wanting. It was a constant pounding need like her worst nights from before magnified a hundred times. All the sexual frustration and desire she'd known as a human was compressed and amplified till it throbbed in her mind and made her knees weak.

Rose wanted the Doctor. She needed the Doctor. If his loss of weight and constant inability to meet her eye was any indication, he was in the same predicament.

The book didn't cover any of it.

There was a whole chapter on the mental telepathic abilities of the species. It seemed all of Gallifrey had once been linked, like an almost hive mind on a subliminal level. There was an oblique reference to a bygone practice of marriage links between individuals, but the book said that wasn't necessary any longer. It said that since the communal link had been developed it was no longer a requirement. Rose had a bad feeling what that might mean.

All this listing and cataloging wasn't helping, Rose decided with a long suffering sigh. She'd felt the TARDIS land a little while ago and, resigned to not having any answers to her questions, Rose stood up and left to find out exactly what sort of trouble the Doctor had in mind for the day.

Exactly two hours later Rose really wished she'd stayed in bed and color coded her list.

The planet was inhabited by mean tempered creatures that looked vaguely like emus only with arms and hands instead of wings. They'd not been pleased to have visitors. They'd arrested her and the Doctor and given them a rather unpleasant death sentence. A little jiggery-pokery with the sonic screwdriver had gotten them out of the cell, but not before the bird things had released the gas.

Rose's hand was firmly in the Doctor's as they ran full out for the ship. Rose realized rather quickly she wasn't breathing, but that she was still moving. It had happened as soon as the gas had hit her nose, her lungs had simply stopped drawing in air. That had been the exact moment the Doctor had pushed open the cell door, grabbed her hand, and taken off for the TARDIS.

It wasn't far, but Rose was already feeling light headed. She tried to take a breath once they'd cleared the poison gas, but nothing happened. They crashed into the doors and the Doctor unlocked them, pushing her inside. She clung to the post and tried again to breathe, no air still getting into her system, her throat feeling like it was plugged.

The Doctor didn't appear to notice. He was grinning and flipping dials. The TARDIS gave a lurch and they dematerialized. He swung around the console and skipped down the steps.

"Well, that was unexpected!" He smiled wide and ruffled his hair a little contritely. "I suppose I should have warned you they'd met me before."

Rose didn't say anything, just looked at him with panic in her eyes. She was vaguely aware that she must look a bit like a fish out of water, with her mouth gasping for air it couldn't take in, and as she sunk down to the grating she had the odd mental image of herself starting to flop around.

The Doctor gaped at her for a moment before quickly falling to the ground next to her.

"Rose," He touched her hand and she frantically grabbed his, still struggling to inhale and not succeeding, hysteria beginning to set in. "ROSE!" He shouted her name and brushed her hair away from her face. "Breathe, Rose." His eyes were large as he gazed down at her. "The gas is gone, you can breathe now. It's normal, you're okay."

Panic had fully set in and Rose could barely make out his words, her fear making everything worse. She needed air, and badly. It had been almost 15 min since her last breath, and most of the time had been spent running. The Doctor could go for an hour without air but her vision was starting to go black. Her panic making her hearts work faster and using up what oxygen she had in her system rapidly.

"Rose, it's your respiratory bypass." The Doctor shook her a tiny bit trying to get her to look at him. "It kicked in when they released the gas. You have to relax, Rose. Let your body work." Her eyes were starting to roll up into her head and it was the Doctor's turn to start panicking. "Rose, you have to relax!"

Rose couldn't hear him anymore, there was a constant ringing in her ears and the console room had faded to darkness. She was still gulping, struggling to try and force air into her lungs and it wasn't working. Her head was pounding, and then suddenly it was like a damn burst.

The Doctor. He was in her head. She could feel his fingers on her temple and she could feel him in her mind like a blast of tepid air. It was like his hand reached out and flipped a switch in her chest and suddenly she was breathing again, air rushing into her lungs, her vision clearing.

When she finally stopped hyperventilating, she realized she was in his lap and the Doctor was crying and rocking her back and forth, one hand still at her temple. His presence was still hovering in her mind and she could feel his fear. Rose closed her eyes and let herself swim in his presence.

Rose, I almost lost you! The Doctor's mind screamed at her.

What happened? Rose shivered in his arms and clutched weakly at his jacket.

The Doctor's entire frame trembled. You didn't know how to work your respiratory system, Rose. You almost died! I... the Doctor's mental voice gave what felt like a sob and Rose's hearts thudded heavily. It should have been instinctive, but you didn't seem to be able...

Rose hugged him tighter. My body changed, Doctor, but in my mind I'm still a human. Evidently I didn't get an instinctual instruction manual with the upgrade.

The Doctor choked and let out a startled laugh, hugging her tighter. I had to force you to breathe!

Thanks? Rose offered mentally and the Doctor snorted, not letting her go.

Don't thank me yet, Rose. The Doctor pulled back to look her in the eye and Rose could see and feel his trepidation. I'm afraid that in order to do it, I had to...

Rose closed her eyes briefly before opening them to gaze into the depths of his brown ones. You linked us. We're effectively married aren't we?

The Doctor didn't answer, he just pulled her closer and Rose shivered with what she realized much to her shame was relief. Finally, her mind wasn't empty.