Author's Note: For the last two weeks I've been very ill and the stories I intended to post over the last two weekends just didn't happen. Put up your umbrellas, it's raining one-shots this weekend.

Rated M for mature themes and sexuality. If you aren't old enough to know what estrogen is, you definitely should not be reading this. ;)

The Insidious Influence of Estrogen

Being as self-aware as she always was, Temperance Brennan hummed as she applied a razor to the gentle slope of her lower left leg and considered a question of important investigative inquiry. Was it the sunny promise of a warm spring morning, or the equally sunny promise of a week of ascending estrogen she should thank for her current state of contentment?

To wit, it was that time of the month once more. Her menses fully behind, treacherous ovulation still looming a week out, yet powerful forces of reproductive intent had taken hold of her mind and body already. There was really no reason to shave today, other than that she wanted to, and why did she want to….?

She glanced back out the shower once more, catching another peek of satiny orange lighting up the western wall that had promised a gloriously sunny day ahead. It was that tangerine sheen that had decided her wardrobe would include a skirt today. Which meant she should shave. Which meant it was the sun's fault, really; yet she suspected otherwise. Being a genius did not exempt her from the tidal forces of hormonal surges; rather, it made her a sardonic spectator to her own captivity under their influences on herself, and on Booth.

This month, an experiment was afoot.

Actually, every month an informal study took place whereby Temperance Brennan noted her partner's intensity of interest waxed and waned as predictably as the rise and fall of her estrogen levels. And he had no idea.

It was fascinating.

She smirked.

Today was day eight, and rising levels of Follicular Stimulating Hormone secreted by her pituitary had begun colluding with increasing blood levels of estrogen, causing a feeling of flirty well-being that drove many women to unconsciously enhance their attractiveness in preparation for copulation. She would chose a brighter shade of red lipstick and Booth, just as unknowingly, would be drawn closer to her by some as-yet undefined mystical force.

Pheromones, perhaps.

She always wondered how he just always seemed to know, and yet he didn't know at all. (Because she'd asked him if he was aware that she was on the verge of ovulating last month and had received a quite blank stare in reply. So no, he didn't actually know her reproductive status at any given moment, yet he responded to it on instinct. Something in him knew.)

Was it pheromones, or would he simply respond to her delicious sense of sexy confidence, the same surge that drove her to shave and slather on russet rose lipstick?

Out of the shower and into the closet where she selected a floral skirt and heels, because this month she was actually testing her hypothesis. Variables in clothing, weather, mood, all tracked and recorded because she was that curious. Wouldn't their relationship thrive all the more if she knew what incited his interest? Why not find out if there was a hormonal component or if his reactions to her were more random in nature than nature itself would suggest.

Why not know…?

Sweeping into the kitchen with Christine in arms, Brennan took in the sight of breakfast half cooked and her husband standing at the stove, spatula poised above hotcakes. Situation normal, they did this routine every morning. "That smells good," Brennan remarked.

He turned to grin, and just that fast, before she'd even crossed the kitchen, he was 'checking her out.' (Angela, it seemed, had an extensive slang-riddled vocabulary documenting the behaviors indicative of modern Western mating rituals and this ... the slow slide of his visual tracking up and down her torso ... was a strong indicator of peaking sexual interest.) His attention at this particular moment strongly suggested it was not the skirt, but rather the estrogen that influenced him...

...because she was standing behind the island, her lower half still concealed. He did not yet know she was wearing anything so different from the day before. While pondering, she felt Booth shuffling over to take their daughter and he leaned in with an approving leer, his eyes alight with arousal. "Morning," he purred. "You look grreat."

And he actually growled it.

"I look the same as I did yesterday," she chuckled, certain it was true. Yesterday he'd barely glanced up as she passed by.

"No way, definitely better today." He nuzzled a kiss along her jaw before whirling away with Christine.

Estrogen.

Had to be.

She watched her husband settle their daughter in her seat at the table and shook her head at the blush now staining her cheeks red. Those bulging arms, lifting and shifting Christine into place... Spending her days in the proximity of Booth had brought innumerable distractions for years, but none so severe as a morning amped up on fertility awareness. Hers, of her own; his, every damn day. "How did I ever get any work done," she marveled under her breath.

"What's that?" Booth turned, finally noticing her entire attire with a speculative gleam in his eye. "Nice ... shoes."

He wasn't looking at her shoes.

"Thanks." He kept his eye on her while she crossed over to the refrigerator and didn't shake himself back into awareness until she sniffed delicately and inquired, "Is something burning?"

Booth was moving closer, his eyes holding hers in flirtation. "The only thing burning here is my desire."

"I meant on the stove," she whispered suggestively.

"Huh...? Damn!" Realizing the extent of his distraction, Booth turned just in time to rescue the blistering hotcakes before they turned black.

Come to think of it, she wondered how he ever got any work done on days like today.

With estrogen in ascendance it was unsurprising that Brennan found her thoughts straying towards sex throughout the day. She envisioned enacting all manner of decadent displays of unholy affection for her husband, all of which she could only hope would lead to a very satisfying conclusion of robust intercourse. As the day wore on she actually felt flustered, and an impending flutter of anticipation at seeing Booth again.

Hopefully only half clothed.

(After Christine was safely tucked into bed, of course.)

Over dinner he complimented her skirt when she waltzed by. She smirked, knowing estrogen was to blame but nonetheless enjoying the swing of her hips as her heels clicked against the tiled kitchen floor. Since when did she wear heels in the house? Since now, so she could rule clothing out as a source of Booth's emerging obsession with being closer to her.

Take now, for example. He was supposed to be helping her clean up in the kitchen but he'd found something else to occupy himself with. As she washed the dishes Booth's hands skimmed over her hips and she refrained from fending him off in hope that it would lead to dirtier things than dinner dishes in the sink. "Mmmm," he murmured against the back of her ear. "What perfume are you wearing?"

Moist heat against her ear made her shiver paradoxically, and then laugh as his question registered. "Eau de estrogen."

In other words, she wasn't wearing any perfumes today other than her own body's exotic blend of fertile hormones.

"That sounds terrible." He nuzzled his nose into her hair, laughing low at the unlikely name.

"You seem to like it," she teased right back. Turning, dropping her hands to the counter's edges, she let Booth press himself against her in blatant invitation.

"I like anything you wear," he muttered, pulling her blouse free and proceeding to unbutton it in a bold maneuver that contradicted what he'd just said. "I like it best when it's on the floor." And then, finally! Finally he was kissing her and it was precisely the open-mouthed, erotic kind that she loved. It was almost as if he knew she'd been half distracted by desire for a kiss like this all day long.

His hands sculpting her, his thigh thrusting between hers, his body bending hers backwards over the kitchen counter while he devoured that non-existent perfume and everything else scented with it (which was pretty much included the whole of his wife's willing body). Three cheers for estrogen!

Damn, someone should patent this stuff...

But then the phone rang with a crisis in the lab and she had to rush out, leaving him more than mildly disappointed and her own conjugal aspirations shunted aside for the evening.

~Q~

It was late when she slipped into bed that night and found Booth sound asleep in boxers and a t-shirt. Damn. Instead of completing her estrogen observations she'd spent hours rectifying someone else's error and now she was both tired and disappointed. A shirtless Booth to snuggle into would be one sweet reward after a hard night sorting out the bony remnants of three separate individuals that had been commingled in Zack's old boiler by mistake. (A new term meant new interns, who often posed excruciating headaches because their mistakes tended towards catastrophic rather than merely inconvenient.)

So, Booth was asleep. Considering their aborted escapades after dinner she'd been certain of a warm welcome the moment her weight shifted the mattress, but no. Nothing. Booth remained reclined, shirted and snoring just a little, on his own side of the bed even after she climbed in.

Although she was exhausted, a small part of her waited in suspense to see if her husband would stir and turn to her. She wanted him to and if he wouldn't wake then she could certainly accomplish it with little effort. Just a touch and a whisper would be all that it took. But then she also looked at the unblinking red glare of time, noting sadly that it was already past 1:30 and her morning loomed only a few hours away. Sleep would be the wisest course.

Besides, the estrogen surge typically lasted several days. There was always tomorrow.

With a sigh, she settled and covered herself, feeling the currents of sleep sweep her thoughts away….

…only to feel something slither over her waist and she jerked violently in startled awakening. "Wha…?"

Her body held rigid for a moment as the fog of sleep clouded her perceptions and she moaned in confusion. Someone's hand moved over her belly, sliding up the length of her sternum and abruptly she was pulled back into a hard, hot chest.

"I want to fuck you."

Booth.

Only Booth. Brennan relaxed into him with a sigh, falling half asleep almost immediately despite the odd non-sequitur of what he'd just growled.

"So damn hot," he whispered against the back of her neck, his lips pressing feverish kisses against her skin, moving up along her mastoid process to flick hotly against her earlobe.

"Wha' time is it," she mumbled sleepily.

He didn't reply, instead pressing more kisses against her cheek and ear. Brennan's eyes squicked open, blinking owlishly at the blurry clock just long enough to note the hour had passed 02:17 am; forty five minutes after she'd gone to bed meant he'd interrupted a deep sleep cycle which probably explained why she was still so drowsy.

"'S late," Brennan admonished with a tired moan. Only four hours before she had to get up. Her eyes fell closed.

"Your fault," he accused, hot against her ear.

"I was sleeping." With her back turned to him. She was quite certain of that, so how could she be blamed for his abrupt and inexplicable arousal? Brennan burrowed more deeply into her pillow, determined to return to that restful state of repose as quickly as possible.

But her husband had other ideas. "This body in bed beside me," he assured her. "Totally your fault."

She batted a hand backwards, shocked to find herself fumbling over him au natural. Confusion stalled her hand, as she was certain he'd been wearing a t-shirt and boxers when she got into bed less than an hour ago. "Where are your boxers?"

"They came off," he whispered, as if he'd had nothing to do with obtaining his current state of undress.

"By themselves?" It didn't make sense.

She felt them hanging off one of his thighs and for a brief moment struggled to understand why he'd awakened her and why it was her fault and how his underwear had gone halfway missing seemingly without explanation. But she was too tired to puzzle it out.

"I had a bad dream. And I really want to fuck you." An arm appeared under her left side, and another slipping silently up beneath her t-shirt, pushing fabric out of the way. Despite the coarse words, his touch was gentle.

"Okay." She was too tired to make sense of anything, including the fact that dreams generally did not cause nudity.

Fingertips stroking soothing circles over her belly, up her ribs and along her sides lulled her nearly back to sleep. Booth was always so gentle with her, his coarse hands somehow smoother than silk when they caressed her. Even the heat of him pressing into her from behind, the steaming breaths as he kissed and caressed her neck, throat, ears and cheek could not compete with her exhausted surrender to that tender touch. She drifted away again…

…and felt a shock of pleasure tingle over both of her breasts.

Brennan gasped, startled awake again at the shivery sensation of Booth's fingers circling her areolae and drawing lines of torment from the base of each mound up to the top before he flicked nipples that, somehow and completely unbeknownst to her, had become erect. She felt it pooling deeply below, her body's awakening evidently having preceded her own by several minutes.

"Booth…?"

What was happening?

Behind her, her husband pressed himself up against her, thrusting his length between her legs suggestively. He was roasting her, his heat enveloping her entirely under the stifling blankets. His touch flared over her again, causing her to moan and arch into his hands almost without thought. She felt as if she'd awakened half way through the proceedings, bemused to discover her body could manage its arousal just fine without any input from her mind. Time had passed, she didn't know how much or what was happening other than he was making her body hum with impending pleasure. She was tired and still half asleep but this felt so good….

Perhaps he sensed her indecision. Before she could consider the pros and cons of sleep versus sex when dawn was only hours away, one of his hands abandoned her breast in favor of more fertile territory down south.

The silky caress hit her like electricity, cranking up her arousal instantaneously the moment his unerring fingers found her already fully prepared for his entry. Waves of sleepy pleasure rolled through her, desperation mounting with every pass of his expert fondling and every thrust of his rapier hinting at further and much more effective fulfillment.

Giving herself up to his ministrations (and accepting the practicality of getting back to sleep all the more quickly after an explosive orgasm, as opposed to losing an hour or more to total frustration otherwise, now that he'd magically turned her all the way on), she assented. Brennan reached down to make short work of her own clothing.

It was gone.

A moment later she pressed herself back into him, fumbling to feel him complete her.

And then he was in, the two of them groaning in bliss as they joined.

"Fuck, baby, you feel so good. You're so hot and wet for me." Booth thrust deeply, his fingers stroking her rapidly back into oblivion. Pleasure rippled outwards from his touch, his body plunging deeply into hers and then withdrawing, generating steady sparks with each returning surge.

She went fast, spiraling upwards with the rhythm of his possession. In mere moments pleasure exploded, taking her under so fast she didn't know it was coming. As the crashing waves subsided, Brennan pushed herself forward to escape his heat—it was too intense!—but with an almost insatiable instinct she used the leverage she'd gained to drive herself more deeply against him.

"Oh, like that," he groaned. "I need to fuck you."

He was in so deep, his hands grappling as he thrust desperately into her. His frantic fucking lost all rhythm and yet it drove her straight back into a state of hyper arousal within moments. Pounding erratically, she felt his heat deepen, expanding and burning like a brand just before he cried out a low roar of ecstasy and then he exploded inside of her. The length of him throbbed deeply within her, bringing a little echoing spasm as she came again.

They fell still, both still breathing heavily and now at last the clouds of sleep had parted enough for her to wonder what had happened.

The estrogen experiment had appeared to be a failure. He'd flirted all evening and had even gotten handsy, yet he'd slept through her entry into bed. Most nights when estrogen was in ascension, Booth pounced the moment she was horizontal (not that she minded!). Tonight she'd been soundly sleeping and suddenly he was awake and on the prowl, inexplicably nude and crudely horny.

(That was one of Angela's words, not that hardened keratin made any kind of sense in denoting a desire for intercourse.)

Booth was slipping loose at last. It occurred to her that certain matters required attention and the inherent injustice of their situation made itself known when Booth rolled onto his back with every intention of staying that way for the foreseeable future. She, on the other hand, had to get up.

Grumbling that (sure, she'd had two orgasms but) she'd lost almost forty five minutes of precious sleep and he got to just lie there and he'd started it, Brennan took herself off to their en suite bath. Back to their bed a couple of minutes later once again fully clothed, only to find her husband sprawled sleepily on his back, his boxer shorts still twisted around his right leg and his t-shirt nowhere to be found.

"I still don't understand," Brennan finally ventured, studying his near-complete nudity with all the perplexity of a stymied scientist. "Why weren't you wearing your underwear?"

"I had a bad dream," he repeated as if that should explain everything.

"And what, your clothes fell off?" Highly unlikely.

He grinned, utterly unrepentant. "Yep."

"In your sleep…?"

"Stranger things have happened."

"You're not going to tell me, are you."

"Nope." He did, however, restore his boxers to their proper position.

Brennan settled back into bed but within moments her husband's hands were reaching for her. She sighed, then got up before he could fondle her out of another hour of sleep.

"Where are you going?"

Down to the kitchen and back to the bedroom, Brennan flipped the blankets off to his startled objection and ripped off a piece of duct tape.

"What's going on," he yelped.

"Preventative measures. In case you have another bad dream."

She taped his boxers firmly into place, nodded in satisfaction, then returned to her own side of the bed.

Apparently, her hypothesis about estrogen had received confirmation.

It was the only explanation for bad dreams wherein underwear was removed under mysterious circumstances.

~Q~

Author's Note: I'm not crazy. I might, however, have been under the influence of estrogen when I wrote this... :P

Thanks for reading!