It was dark atop the canyon where the Tardis had settled for the night but for the glittering stars. Although The Doctor had intended to spend the night floating aimlessly in the time vortex, it seemed his dear blue box had other ideas. She'd instead bumped to the ground here, atop a red-brown cliff face in what The Doctor had eventually ascertained was 1950s America, somewhere in the dry desert of the state of Nevada. From his vantage point perched on a tall rock formation, he could just see the garish lights of Las Vegas gleaming a few kilometres off.
Disgruntled as he always was when the Tardis decided to take him on an undirected excursion, the moment he pulled open the push-only door and stepped outside he became too captivated with the gloriously starry night to mind. The air was crisp and clear. Light winds brushed across the arid landscape below, and with the exception of the distant blinking of casino lights in Vegas, he was utterly alone.
Now, for someone who'd spent the majority of his 900 years bouncing around time all by his lonesome in a police box, The Doctor still found himself frequently craving the company of other sentient creatures. The nights he couldn't pick up a companion or two for a little save-the-world adventure were long and often depressing. Some nights he'd be lucky enough to stumble upon River at a place in their convoluted time streams when they both knew each other, but that was becoming less and less frequent.
He was staring blankly at the astonishing sky when he heard a shrill ringing noise from inside the Tardis. Maybe if I ignore it, it'll go away. The ringing repeated thrice more before he grumbled and pushed through the pull-only door into his time machine.
"Oh. You again."
The irritating sound was emitting from a flattened silver box that was sitting atop the console. Some time ago River had gifted him some sort of telephone, one she called a "cell" that could "go on the internet" and do "lots of other wonderful things" he hadn't cared to explore. When he touched the illuminated front screen, the sound stopped and he sighed his relief. He was starting back for the door when he heard a familiarly flirtatious growl of a voice say his name. Oh. I guess that is what most telephones do, isn't it then…?
He picked up the device and lifted it level with his face before answering. "Hello?"
"Hello, Sweetie," River purred down the line.
He was impressed by the quality of the sound coming from the tiny box, but then again his last functioning telephone had been a rotary style he'd borrowed from Winston Churchill.
"H-hi, River. What is it then? Wait, um… how do we do diaries like this?"
"Darling, if I'm able to call you, don't you think I know exactly where—and when—you are at the moment?" she drawled smugly.
"Oh. Well then." The Doctor waited, hoping she'd volunteer some specific reason for calling, or at least where and when she was at the moment. No such answer came. Instead, he heard a soft chuckle followed by what sounded like a moan coming across the line.
"R-River…? Are you there?"
"Oh yes sweetie, but something is terribly wrong…" her voice was even more low and sensual than usual.
"Uh. What?" The Doctor stuttered awkwardly.
"You're not here with me, darling." He heard her loud exhalation, followed by what he was now quite sure was indeed a distinctly sexual moan.
"I… I'm sorry…? I'll let you, um, go now, it seems you might need a little time with, um, your old sonic or some such…"
"No, no, no sweetheart… mmm!… do you mean to say we… we haven't done this yet?"
"Done what… yet? Am I there too?"
"No honey, my dearest beautiful cosmic idiot… I mean phone sexxxx." The Doctor recognized the sound of one of his outdated sonic screwdrivers, humming in the background as she mumbled on drowsily.
"Um. Er. No, we have not."
"Well then. There's a first for everything, yeah, love?"
"Uh… yes, right! So… do I just…?"
"I'll tell you just exactly what you do, sweetie. You take those lovely long fingers of yours, and you wrap them around your… around your cock… are you doing it?" River was speaking a bit breathlessly by that point, and her glorious curls rustled against the receiver noisily as she moved.
The Doctor felt the odd but pleasurable tingling of lust building up fast between his thighs and unzipped his trousers to follow her orders. When his hand found its way into his pants and caressed his sensitive member, he couldn't help but grunt softly. It'd been so so long…
"Mmmm, that's it darling, imagine it's me there, with my lips hot around you…"
"…God, River…"
"…but not too fast love, wait up for me…"
"…or," The Doctor said hesitantly, "I um… I could just speed things up a bit." At her whimpered reply he decided he'd risk trying his hand at her brilliant little game.
"Pretend… pretend I'm there, there with you…"
"Mmhmm, yes love…"
"And… River, what are you wearing?"
"…nothing," she giggled, and he could picture the exact suggestive little smirk she wore.
"All the better for my plan, then. And I'm feeling your… your breasts, your fabulous breasts and then my tongue moves down to touch at their tips and…"
"…and I'm fisting my hands in your adorable floppy hair, and we're rocking together, and we're oh so close now and…"
"Bloody hell, River, why haven't we done this before?"
"I thought we had!" she cried, a mixture of arousal and bewildered frustration.
"Well never mind that now! Are you… are you really close?"
River moaned before finding the words to answer properly. "Yessss, and you're inside me, and oh it's perfect, and…"
She came with a scream, and The Doctor followed seconds later with a grunt of pleasure, stars clouding his eyes. When they'd collected themselves and more or less regularized their breathing a couple of minutes later, River was the one to break the warm silence.
"I love you, Doctor," she whispered, a smile in her sultry voice.
"I love you too, River," he said.
After that, they stayed silently on the line together until she fell asleep. River was lying with her hair splayed out around her head and nothing but a sheet covering her body atop her cot in Stormcage, her phone beside her and a sweet smile curling her lips. The Doctor, millennia away, settled down on a blanket and looked out over the edge of the canyon. The green and yellow and blue lights of Las Vegas twinkled beautifully in the distance, and he listened to her breathing slow into that of slumber before clicking the call off.
"Bless you, Sexy," he said, giving his dear Tardis an affectionate pat on the door, and he pushed open the pull only door and tripped inside. Fixing his eyes on the console screen, he took a deep breath and flew off into the time stream once more to save yet another world.