They were enemies. That's all it came down to. His sworn enemy, the man who had murdered thousands, threatened the ones he loved. He was capable of unspeakable crimes, he had haunted the Doctor's nightmares for years on end. This was wrong, so very wrong.
But God, his lips felt good.
He didn't even know how they got there. One minute they were facing each other from across the TARDIS as sworn enemies, and the next they were in a tangled web of surpressed lust spilling out from the both of them like the flood after the dam had broken. He planted kisses all over the Doctor's neck as his hands explored the Doctor's body. The Doctor felt a low moan deep in his throat and dug his fingernails into his back when his lips started to trail down to his collar bone, gently biting and licking at the area. The Doctor gasped when his hands found their way down his trousers into the crevice of his inner thigh.
"Master," he breathed as his fingers began teasing his length. The Master felt his heart speed and his breath hitch at the sound of the Doctor saying his name. He had longed to hear it from his lips again, not forgetting the pleasure it gave him to hear the last time the Doctor and he had met. The Master growled possessively and gripped him, receiving the reaction he had hoped for.
The Doctor seemed to have lost his voice, throwing his head up and closing his eyes, his jaw dropping open in pleasure as nothing but moans escaped his mouth when the Master began sliding his hand up and down his length, wetting his fingers with the precum emerging from the Doctor for less friction. He steadily grew harder at the sight of him; the Master had longed to be the one to make the Doctor fall to pieces in front of him, but he hadn't quite imagined it like this.
As overwhelmingly arousing it was to see the Doctor in this state, sitting shirtless on the console and holding on for dear life, the Master needed more. He needed to let the Doctor know that nobody else could touch him, that he was HIS Doctor, not some black girl who tried to save the world or some blonde girl who could absorb the time-vortex of the TARDIS. Nobody else could make him feel the way the Master did, could make him scream as loud in the orgasm the Master ached to give him, and the Doctor knew it. But perhaps he needed reminding.
He knew the Doctor was close, and he hastened his pace, receiving cries of approval from the Doctor. The Doctor gripped the edges of the console so tight that his knuckles turned white, but the Master wasn't done with him yet. He removed his hand and the Doctor nearly cried out in need. He opened his eyes and looked at the Master with pleading eyes.
"Please," he begged breathlessly. The Master felt himself get considerably harder (if that was possible) and damn near came right then and there. He restrained himself though, and returned to attacking the Doctor's jawline.
"Oh, no, Doctor. You know I can't do that." He breathed into his ear, "I want to hear you screaming my name."
The Doctor began to unbutton the Master's shirt and slid it off his shoulders as he flicked his tongue all over the Doctor's body, tracing down from his neck to the place he most desired him to be. He was instantly grateful for regeneration as his eyes raked the Master's body; he found it hard to believe that he would be feeling this way about the old man he met on their first visit. The Master got to his knees in front of the Doctor and yanked off his pants, casting them on top of the growing pile of clothes. He rubbed the inside of the Doctors legs and placed his lips so close to him that the Doctor could feel his hot breath on his shaft when he spoke.
"Tell me, Doctor, how bad do you want it?" He purred. The Doctor was trembling by this point, barely keeping a hold on himself.
"I would do anything," he managed to choke out and the Master chuckled, his breath sending shivers up the Doctor's spine, "Please, Master."
There it was, that feeling again. The Master felt almost as overwhelmed as the first time; hearing his name from the Doctor's lips would never get old, especially not in such a state as this. The Master gave in and took the Doctor into his mouth, first as a whole and then sliding almost all the way back out again to the tip.
The Doctor cried out and grabbed fistfulls of the Master's hair, keeping him there. The Master experimented a little with his tongue and lips on what made the Doctor simply moan and what made him cry out in pleasure. The Doctor began bucking his hips involuntarily and the Master held him in place at risk of getting his throat fucked raw.
Soon, the Doctor couldn't control it any longer and was blinded by his intense orgasm as he emptied himself inside the Master's mouth. He swallowed willingly and stood, wiping his mouth and staring into the Doctor's eyes. The Doctor stared for a second before desperately jumping down from the console and unbuttoning the Master's trousers and gripping his length.
The Master growled once more and closed his eyes as he leaned into his hand, letting the Doctor repay the favor for a few seconds before grabbing his hand and pulling it away regretfully. He used the hand to spin the Doctor around and he put his arms on either side of his body, trapping him there. He leaned forward, rubbing his length over the inside of the Doctor's bum and a small whimper of desire came from the Doctor's throat as he was teased.
All at once the Master was inside him, and the Time-Lords both gave out hoarse cries of pleasure. Knowing all there is about the Time-Lord anatomy, the Master was able to pinpoint the delicious bundle of nerves quite easily, receiving ear-shattering cries from the Doctor under him. The Master began to lose his steady rhythm in his lust and start thrusting harder and faster, leaning closer to the Doctor's ear.
"Mine," he managed to get out through gritted teeth, and the Doctor nodded furiously in reply.
"Yours, always yours." He breathed and the Master felt his walls starting to close tight around him. Not long after, the Doctor came all over the console, screaming the Master's name at the top of his lungs. The Master smiled triumphantly before his own orgasm came and he fell forward onto the console with the Doctor underneath him. He pulled out and fell back onto the couch, pulling the Doctor with him.
The door of the TARDIS began to jiggle just then, but neither the Master or the Doctor moved. It was undoubtedly Martha, coming back from God-knows-where.
"Should we tell her?" The Master asked. The Doctor shook his head and stuck out his lip thoughtfully.
"No, she'll figure it out." He smiled that smile that the Master loved and pulled him in for a kiss as the door flung open.