She hadn’t been expecting this, but then often the best things did happen unexpectedly.
O is surprisingly demanding in the way he kisses her, one hand clenched tight in her hair and the other on her hip keeping her pinned against the Tardis wardrobe wall they’d stumbled back into. It occurs to her that this is the first time she’d done this - kissing - in this regeneration, and she decides immediately that she’s quite partial to it this time around.
Especially with O.
His hands are sliding beneath her clothes, pushing under the unbuttoned shirt she’d thrown on and smoothing up over her torso, groping a handful of - oh. Breasts. She keeps forgetting about those.
The Doctor breaks from O’s mouth, gasping, and he looks into her eyes as he feels her up quite enthusiastically beneath her clothes.
“I’ve wanted you since the first time we met,” he’s murmuring to her hotly, and the Doctor leans back against the wall, panting, and stares at him.
“But - I wasn’t - I’m not the same as I was then. I was a man,” she emphasises.
“You’re still you,” O breathes simply, and the Doctor inhales sharply, the words making her hearts quicken. Humans usually had trouble getting their heads around a change of regeneration - let alone a change of gender to go with it, and yet here was O, saying things like that as if it were the most simple thing in the world. She thrusts her hands into his hair and drags his mouth back in to hers, kissing him deeply as she moans softly. When he slips his hand down and slides it beneath the waistband of her trousers she doesn’t stop him, leaning back into the wall and parting her thighs, moaning into his mouth when his fingers slip down and touch her where she is wet and aching and new.
He’s gentle with her, his fingers probing and delving though slick folds - wet. That was another new sensation. Her mouth breaks from his in a gasp when he presses a finger up inside her, and she clutches tight to his hair, eyes squeezing shut as she absorbs the new sensation. She likes it, the Doctor decides after a few seconds, as O strokes her carefully inside, nudging up against her clit and making her gasp and gasp.
Eyes snap open to lock onto his dark ones, and fumbling a bit, limbs turned a little shaky from his ministrations, she shoves one of her own hands down inside O’s trousers finding him silky and hard beneath her touch. She wraps her hand around him - smaller hands this time, she remembers… or perhaps O was particularly large. She squeezes him as another rush of pleasure goes straight to her core at that, making her clench around O’s questing fingers. That’s new too, and it makes both of them gasp as she starts to stroke him, her hand matching the rhythm of O’s fingers.
When they come it’s with their eyes locked onto each other, and the Doctor doesn’t remember the last time a human made her feel this good.