Watching her becomes his new hobby.
He's always watched her, always had her in his peripheral, always glanced at her here and then when he thought she wasn't looking, but this is new. This is a new and dark need that he found in himself after his encounter in her bedroom, the one where he might have watched her sleep and then watcher her touch herself and all the while touched himself in return. That night that had slipped into his mind like a comforting item, a blanket or a trinket that he grasped for when the sickness of his own rage got to be too much.
Watching Rose when she really and truly had no idea he was there became the only fix for his madness. No more prostitutes, no more women with broken hearts and judging eyes. He needed Rose, the real and present Rose, and he needed her often. He had schemed up a few ideas for curing himself after that night, repulsed by his own actions, but they involved either regeneration or taking Rose home for good, and both thoughts only replaced the battle-born emptiness with a loneliness that he knew he wasn't strong enough to handle. So he watched her, here and there, and in return he got days of peace. Days where his mind quieted and he could focus on helping and doing good in the universe without quite the effort it took before, without the chatter in his mind that constantly reminded him how alone he was, how evil he was.
Private moments, those were the best. Not just private like she was having a cuppa in the kitchen alone, but private like she discarded her clothes and walked around her bedroom uninhibited. He found her doing just that one day when her door was slightly cracked. They'd spent the day collecting samples from a rainforest on a deserted planet, running from wild animals and trying to avoid the sink holes, and Rose had, he was sure, looked knackered when they stumbled into the TARDIS. He'd planned to stroll by her room very casually, see if she was asleep, see if she needed anything, but he'd found her door cracked. And he heard her humming. And he was lost from there.
Lining his eye up with the crack, the Doctor had been amused to find Rose dancing around her room in nothing but her knickers. She was singing to herself, and he realized she had those little earbuds in, was listening to music, and he wished he could hear the sounds too. Her knickers were black, which surprised him because he assumed everything she owned was pink, and her breasts looked full and different than they had when she had been laying in her bed. Bouncing all around like this, the Doctor noted, gave him a different and appealing perspective.
The tightness in his pants was nearly immediate, and he felt that greedy itch inside himself, begging to do the revolting thing that he loved to do while looking at her. The Doctor tuned his ears into the ship, trying to figure out where Jack was, had to be absolutely sure that he wouldn't stumble upon the Doctor doing that and get the wrong idea...again. When he was confident that Jack was in his room, the Doctor exhaled deeply and let his hand rub himself through his trousers, satisfying that filthy need for friction. Rose had her eyes closed while she danced, her hands up and in her own hair, then sliding down her body as her mouth moved with the words he couldn't make out. That little wrinkle in her hip as she twisted and turned, he loved that crease, wanted to lick it, nibble it. She turned her back to him, and there was that bum. He was obsessed with her behind, and spent far too many hours each day thinking of ways to both worship and punish it.
The Doctor's breath was unsteady as he forced himself to admit what he was doing. He was spying on his companion. At this point, he reasoned, he was so far gone that he didn't know if there could ever be redemption. In his next body, he'd still be paying for these wrongs. The right thing, or at least, the more right thing to do, would be to go to his room now and finish himself off in peace. Use these images of her bare body while he stroked himself in privacy, but he wasn't a right kind of guy. This body was full of treason and harm and greed, and no matter how many times he smiled at Rose each day, how many times he gave her the face of her Doctor when inside he felt like a completely different and raw Doctor, he was still a perverted and desperate Time Lord with an obsession called Rose Tyler.
Belt buckle undone, zip down, pants pushed down to his thighs, the Doctor grasped his erection and focused his eye on Rose, positive that keeping her in his line of sight would prevent him from getting caught. And that worry that he might get caught kept him pumping, kept him going, moved his body from aroused to manic with need. One hand braced against the frame of the door, the Doctor ground his hips into his fist, made himself raw from the dry need of it all. He moved his thumbs in circles around the head of his cock, guiding that bit of moisture down his shaft, an agonizing process that he tried not to think would be easier if it were Rose's saliva instead. A fleeting image of the woman on her knees in her kitchen, her sticky mouth and her freckled forehead came to him, but he pushed it away. He needed Rose, needed to come because of Rose.
His companion surprised him when she hooked her thumbs in her knickers and slipped them down her hips. He hadn't expected a show, but he was pleased, and his movements sped up. Rose shook her bare behind around the room as she flipped through piles of clothes, her thighs rubbing together and then separating now and then, giving him the smallest little eye full. Finding purchase, Rose slipped a satin looking gown over her head, and the Doctor pumped faster as his view of her body disappeared. Almost there.
She didn't put new knickers on, though, and that kept him focused. Her bum was bare beneath that gown, and he squeezed his cock while staring. The sickness started talking then, trying to convince him to enter the room, she wouldn't even hear him come in with those buds in her ear. Told him to come up behind her, bend his knees, and he'd slide right into her with just a quick thrust, and she'd scream and shout but he'd grasp her hips, thrust again, and she'd be scared and probably not moist, but maybe she'd keep her head facing away from him, maybe she'd think it were Jack, and maybe he'd fuck her until she was moist, until she came around him like the little prick tease that she was.
Teeth clenched together, he pushed the voice away and watched Rose flop on to her stomach on her bed, watcher her bend her legs at the knee, watched her little ankles cross together and her toes wiggle as she lounged. He could hold those ankles in his hands, use them to spread her open, like levers or gears and just plunge right in, pound his hips into her behind as she screamed, tried to twist around and see his face. Would she hate his face? Be horrified that it was him and not her pretty Captain come to have his way with her?
And it was disgusting, but he imagined it was Jack in there, doing just that. Imagined she was opening her legs willingly for the time agent, and he came with a groan that he didn't even try to stifle. The Doctor milked his orgasm, his mouth open, his eyes glued to her legs. Stumbling backwards, the Doctor fell into the wall opposite her door, his body shaking with the pleasure of his own disgusting actions.
Trousers mostly righted, he hurried down the hall, desperate to find his door, desperate to be away from her and his shame and her bum. What he was doing was wrong, terribly unkind, not very Doctor-like at all, and he needed to stop. Not being obsessed with Rose hardly seemed like an option, but maybe she wouldn't be so opposed to helping him with his problems. Maybe she'd pity him and his broken soul, comfort him the way he always did for her.
A smile ghosted over his lips as he began planning.
