Author's Note: I'm going to try and write Jack and River in a fanfiction and maintain a level that is strictly K+. Note that I said try.
"WE'RE CRASHINNNGGGG," the Doctor bellowed as the TARDIS spiraled wildly out of control.
"JACK, I'M GOING TO KILL YOU,"
"AGAIN,"
Five minutes previously.
The Doctor and Donna had just returned from saving the third moon of Jargon in the dimension of Platonic, fifth galaxy from the left (take a left at Albuquerque and straight on till morning, you can't miss it). Donna was relaxing on the conveniently placed chairs surrounding the TARDIS controls. Suddenly she was jolted to her feet. Something had hit the TARDIS. The Doctor worriedly checked the controls. Finding nothing wrong, he glanced at the door.
"Not again," he groaned.
"Hold on, DonnnnNNNNNAAAAA,"
That's how they arrived at the aforementioned scenario.
Sure enough, when the TARDIS had landed none too gently on the nearest planet, the Doctor's worst fears were disturbingly confirmed.
"Doooocccctttooooorrrrrrrrr~," a voice sang from outside of the TARDIS.
Captain Jack was back.
"Donna, cover your ears!"
Donna put her hands on her hips as best she could (quite well, considering that she had landed in the swimming pool and was sopping wet) and gave the Doctor a look that could've easily curdled milk. Clearly she didn't think the (ridiculously attractive) fellow outside was worth all the fuss he had received.
" Doooocccctttooooorrrrrrrrr~," It, rather Jack, called again. Donna threw open the doors, only to be met with what appeared to be a face-breakingly high eyebrow raise. She fainted.
The Doctor caught her and moved her away from Jack's influence (it radiated from him like a virus).
"What do you want?" He asked.
"Hermione Granger. And a rocket ship. No, wait; I want to be a starship ranger. That's not it, I want to protect our world from devastation, unite all people within out nation. Hold on, I have it; I want you to want me. Close but no cigar. I want to be the hero Gotham deserves but not the one it needs right now-"
"WHAT DO YOU WANT JACK,"
Jack sighed theatrically. "Fine," he said. "I came here to tell you that five minutes from now, a TARDIS is going to crash land here and WE'RE GOING TO HAVE A PARADOX~,"
Jack skipped merrily about the TARDIS, holding the still limp Donna. The Doctor glared at the immortal pain in his rear end and turned his attention to the controls. He hastily started to negotiate liftoff, only to find that the TARDIS wasn't responding. A check engine light blinked brightly in the corner, indicating that the TARDIS required time to rest and wouldn't be leaving anytime soon. The Doctor held his head in his hands and tried not to kill Jack, who had, by this point, begun to prance about.
The actual event itself was rather disappointing.
River had turned on the Folgenbat (a very complicated doohickey), causing the TARDIS to land bereft of it's usual sound. She whirled around to the Doctor and grinned at him. The Ponds were on Holiday with Brian, and as such, River had essentially kidnapped the Doctor.
"Where are we then?" River inquired. The Doctor laughed.
"You tell me," he said.
"Shall we find out?"
They ran out of the TARDIS only to see...the TARDIS. The Doctor turned back to his own beloved TARDIS, and then back to the one now sitting before him. He turned to River, the corners of his mouth lifting, and arched a non-existent eyebrow at her. She winked in return and they both swung open the doors and marched inside.
The next several minutes of this fanfiction were so entirely filled with innuendos that it is unfit to be here set down. The mixture of River Song with Jack Harkness proved too much for humanity and is forever lost to time. The two Doctors hastily grabbed the now alert Donna and dragged her down into the kitchen. She was, however, having none of that and dragged the two of them back to the main room. She pushed them at River and Jack.
"DEAL WITH YOUR OWN PROBLEMS, YOU SKINNY GITS," she bellowed. She then proceeded to hug Jack. The tenth and eleventh incarnations of the time lord looked from Donna (who'd fainted again), to the Innuendo Squad (catchy, right?), to each other. They nodded in sync. Making a mad dash for the door they just barely made it to Eleven's TARDIS in time to barricade themselves in. They hastily put together some mind wiping devices made from a toothbrush and a cucumber. Armed with that, they advanced towards the doors of the TARDIS. Exactly five seconds before they reached the door, River and Jack traveled back in time two minutes.
Some weird timey-wimey stuff happened and long story short, Jack and River erm, you know what, let's leave it there.
So, the gang started traveling together and were eventually joined by all the previous regenerations and companions and everyone got married and went out to dinner. Except for a minor character in the second season that was eaten by an alien.
AND THEY ALL LIVED HAPPILY EVER AFTER AND NOTHING DIED.
THE END.