It had been a perfectly normal and pleasant day for the two of them, the Master had thought as he'd walked hand in hand with the Doctor through some little back alley. He'd taken his Doctor to a little planet to visit - it was all his arrangements, and he hadn't even let him see the co-ordinates of where they were going. It had all been going so well until a familiar figure came into view. Captain Jack Harkness... Of all of the Doctor's past companions they had to bump into, Jack had to be the worse, because if there was one thing the Master absolutely hated, it was someone else flirting with his Doctor, and if there was one thing Captain Jack Harkness could never resist, it was flirting with anything that moved, especially the Doctor. And today was no different. Practically everything that infuriating freak said was flirting, although the Doctor seemed oblivious to it as usual, which was a good thing, he supposed, as it meant he was more or less impervious to it too... But still, it was quite painful to watch as they conversed, and he stood there, rather possessively clinging onto the Doctor, and trying not to get wound up.
It didn't take too long, however, before the Captain started looking very jealous of the fact that the Doctor was ignoring his every attempt, but perfectly happy for the Master to cling possessively to him, without him making any comment or anything. And that's when an idea came into the Master's head. He was going to make Jack even more jealous, and show him once and for all who the Doctor belonged to, and that he should keep off his property. So, the moment the next break in the conversation came (he wasn't rude, after all, unlike Mr. Rude and Not Ginger), he made the most of it, pulling the Doctor close, pressing right up against him in a very provocative way, which in any other situation would probably have lead to a lot more than what he intended right now, and kissed him. Hard. Passionately. And smirked slightly as the Doctor responded with equal passion, rather enthusiastically. When he finally broke away, slightly breathless and very pleased with himself (especially since he could see a rather obvious sign in a certain part of the Doctor's anatomy that he would be perfectly happy to continue as they might normally do right now), he couldn't help but smirk more at the look on Captain Jack's face. The mix of pure jealousy over the fact that this other Time Lord who wasn't too high in his good books had just kissed the Time Lord who he had fallen for pretty much from the first time they met, and slight arousal at having watched the two Time Lords kissing. Oh that was better than he'd ever hoped for, knowing that it would drive Jack absolutely crazy, especially as the Master shot the Doctor a very seductive look which quite clearly said that when they got back to the TARDIS he would be finishing what he started out here, and caught the look of longing in Jack's eyes. As if he'd ever let him anywhere near his Doctor. But still, he was sure he'd made it perfectly clear who the Doctor belonged to. So when the Doctor suggested that maybe he didn't have to cling on to him like that all the time that he was talking to his friend, the Master agreed, letting him go so he could finish his conversation with Jack and taking a slight step back.
He regretted it almost immediately, as before either of them had realised what was happening, Jack wasn't just touching his Doctor, but had pinned him against the nearest wall with his whole body, grabbed his tie to pull him in closer, with his typical flirtatious look, and snogged him, about as hard as the Master just had. And with the Doctor aroused by the Master's previous advances as he was, he wasn't putting up quite the struggle he might usually have, although there were definite signs that this wasn't entirely welcome (but then again he didn't seem to find it entirely unwelcome either, much to the Master's annoyance). The freak was snogging his Doctor. He didn't care what the Doctor thought. The freak was dead. The moment he let go of his Doctor (he didn't want to damage his Doctor, even if he wasn't fighting it off as much as he might like), he was dead, as many times as it took to get it drilled in to that thick skull of his that his Doctor was off limits. Especially to freaks like him.
When Jack finally, after what felt like hours to the Master, released the Doctor, he was fuming, and when Jack flashed him a smug look of victory (the Doctor was still leaning, slightly stunned against the wall after that, not entirely sure how to react), he snapped, searching his pockets for the laser screwdriver, and on finding he'd left it behind, lunged for Jack with all his strength, determined to make him pay. The Doctor, meanwhile, watched on helplessly as the other two men literally fought over him, the Master angry that Jack would dare touch his Doctor after they'd both made it so clear who he belonged to, Jack still angry with him for the year that never was, and not quite able to believe that the Doctor was actually fully consenting in their relationship, determined to rescue him.
It was quite some time before the Doctor managed to get over the shock enough to react to it properly, and step in to try to split his friend and his lover apart. And when that didn't work, he did the only thing he could think of to distract their attention from fighting each other, whimpering slightly as though about to cry. That stopped them as Jack and the Master turned, each determined to prove that they could do a better job of comforting the other Time Lord, and hence win his affections. Which is the moment when the Doctor stepped up to the Master and forcibly pulled him away.
"Look, as flattered as I am by your obsessions for me, there's really no need to fight. As good a kisser as you are, Captain, I made my choice a long time ago. I'm sorry... And Master, I know you're jealous and possessive, and it is something I love about you in some ways, but really, there's no need to attack my friend like that. Okay?!"
Both men nodded slightly, although the Master made it absolutely clear with his glare that they would be discussing this later. The Doctor rolled his eyes, bidding Jack farewell, with a warning gaze that told him maybe he should keep his distance from now on... And then to prove his point to the Master, pulled him close, kissing him deeply, letting him take over, and claim him back... Maybe, the Master thought as he escorted his Doctor away from the freak, this day wasn't such a total disaster after all...