My "New Earth" episode tag, "02 01 New New Doctor", demanded a sequel, and this was the place for it :)

As yet un-beta'd.

Chapter 6 - Tastes Like Victory

Rose's heart was racing as she calmly stepped from the TARDIS' kitchen, leaving the Doctor behind her. She'd done it. She'd crossed the invisible Line.

She had actually addressed the issue of physical-interaction-without-imminent-or-resolved-peril, both verbally and, well, physically.

With the Doctor!

And he hadn't bolted.

Rose grinned to herself, as she scuffed her slippers along the grating of the TARIDS corridor, heading back towards her bedroom. With as bold as she'd been with boys in her past, it amazed her to think of how carefully she was treating the potentially skittish Doctor.

Of course, if she scared him off, it would be a whole lot more significantly life-changing for her than altered playground or pub dynamics...

Rose licked her lips, a little disappointed to be tasting hot chocolate rather than Doctor. It was good hot chocolate, but still... That tiny kiss - had that actually been their first, deliberate, non-life-and-death kiss?

Time Vortex - that was to save her life, obviously.

That morning over Christmas - too brief and way too spontaneous to even consider, really.

After the Wire - if she hadn't been so terrified and desperate, that snog before she fell asleep in his arms would have been... Alright, so it was still spectacular, and delicious, and seared into her memory - but locked away with a big, "Do Not Mention" sign.

Leaving Krop Tor - definitely deliberate, magnificent, etc., but also too brief for her satisfaction, and most definitely the result of their post-peril relief to be reunited.

Hang on.

Why did her mental et cetera just include "delicious" again?

She ran her tongue over her teeth. That taste... it was there, before. That taste, that psychograft/Bad Wolf taste, wasn't it? After the Wire... She'd fallen asleep, and woken up with morning breath, but... it had been there! She'd forgotten between waking up with the Doctor and then toothpaste...

And after leaving Ida with Zach and Danny... the TARDIS had to be recalibrated or some such, then her Mum had called... But he'd kissed her, and that taste was there...

Rose stopped in the corridor, and turned about, heading resolutely back towards the kitchen.

She raised her eyes, thinking at the TARDIS. "I was assumin' it was the psychic stuff," Rose said aloud. "But he never actually said, after Cassandra. So, I'm thinkin' it's one of two things," she went on, debating with the sentient ship that never actually answered her in words. "One, the Doctor's gettin' in my head whenever we kiss," she felt a thrill at the thought, despite it being the less likely of her suspicions, "or two... he kissed Cassandra? Me? When she'd taken over my brain?"

The lighting in the corridor seemed to shift, and Rose was filled with a sense of relief and pride that wasn't quite her own.

Her eyes narrowed at the kitchen doorway.

Before she entered, Rose schooled her features, lest the Doctor immediately pick up on her suspicions. He was still there, she saw, putting away the last of the hot chocolate ingredients, apparently licking some whipped cream from his finger as he closed the refrigerator door.

"Doctor, technical question," Rose said by way of greeting, strolling up to him and leaning against the fridge.

"Certainly," he told her, leaning back against the kitchen counter and wiping his hands on a dish towel.

Rose gave him her best innocent smile. "What's a psychograft taste like?" she asked as he tossed the towel back onto the counter and crossed his arms.

The Doctor stared at her, blinking, his expression otherwise frozen as if he were still patiently waiting for her question.

Rose tilted her head. "Doctor?" she prompted, sweetly.

Knowing his highly-touted, Time Lord mental abilities, she was sure he was replaying their long-ago med bay conversation, desperately trying to find a loophole in where he should have corrected her taste assumptions if he hadn't actually been guilty of what she now strongly suspected... He blinked again at her, then slowly opened his mouth to speak, as if hoping the right words would come out if he could just make way for them -

"Did you kiss Cassandra?" Rose asked point blank, emboldened by his and the TARDIS' combined reactions.

His eyes widened comically, and his mouth dropped fully open. "That - that- she kissed me!" he stuttered out. "You did - I didn't know it wasn't you!" Rose guessed he was regretting having opened his lips, because now there was nothing holding back his responses. "Could've been playing some kind of game or something," he scrambled, "or just finally overcome by my... Wrong, is what it tastes like," he told her, nodding, wagging a finger at her. "Psychograft - it tastes all wrong. But how was I supposed to know? Last time it was all mixed with Time Vortex. Thought maybe it was just something you'd had for breakfast when I wasn't looking. Or you hadn't brushed. But nothing'd smelled off earlier... maybe you'd stopped by the cafeteria on your way up to Ward 26; how should I know?!"

She gave him a moment after he finally managed to snap his mouth shut, his arms now tightened defensively across his chest. "Hm," she told him at last, with a single nod.

"Hm?" he repeated.

"Well," she explained, "ya never really answered me when I was talkin' about that taste before, when I thought it was from the brain squeeze. I take it that wasn't it?" she asked.

"Ah, well, no, not technically, no," he admitted, dropping his hands to grip the edge of the counter behind him.

"That was you?" she asked with a raised eyebrow, and he nodded weakly. "I mean, how hard were you kissin' me for it to still taste like that after we were all done an' in the TARDIS?" she asked, shifting a hand to her hip.

"Serotonin!" he blurted out. "The serotonin receptors on your taste buds are particularly highly concentrated, and the psychograft probably amplified the effect, putting all that pressure on your hypothalamus. And you kissed me!" he reiterated as an afterthought.

Rose smirked. "Serotonin," she echoed, nodding. She cocked her head, thoughtfully. "Isn't that a mood chemical?" she asked, genuinely curious.

The Doctor seemed grateful for the topic shift to plain old biochemistry. "It's a hormone, a neurochemical," he told her. "Sort of the self-esteem booster of the chemistry of happiness... actually," he trailed off, relaxing into a more thoughtful posture, tugging one hand on his ear, "maybe that's why you snogged me like that."

"Hey, wasn't me!" Rose defended, possessively determined that if there was going to be any snogging these days, particularly involving the Doctor's lips and taste buds - and especially her own - that she wanted to be able to remember.

The first time around.

His hand shifted to his neck, as he looked satisfyingly contrite. "Course not; sorry," he offered.

"Alright," she told him, nodding her forgiveness as she pushed off from the fridge. "So, next time, make sure it's me," she told him firmly, spinning around towards the exit without waiting for his response.

"Next time?" she heard him ask with a smile in his voice.

She trailed her hand along the doorframe as she slowed, still not looking back. "Really does taste better than chocolate," she confirmed, before gracefully fleeing towards her room.

The end.

So, there was this Cornell University study on the effect of happiness on the tastiness of ice cream... Interested parties can search for Robin Dando, "Just How Sweet Is The Taste Of Victory?"

"02 11 Show Her, Tell Her" is next, covering the before and after for "Fear Her".