A lot of talking, some drinking and crying, some really awkward semi-sexiness... but not really. I hope Martha's reasoning seems sound and "organic" (her word) to you, and not just an excuse to get the Doctor interested. Because in my mind, she is absolutely dreading this. For now.
IV
In what the Doctor jokingly called "The Salon," (usually in an exaggerated French accent) because it was the fanciest, most lush, comfy room in the TARDIS, the two of them sat on the red sofa. As Martha cradled a cup of tea and stared wide-eyed at the floor, he told her the whole story of his trip to the Oracles' Abode. He related what the Oracle had said about the "use" of his energy, the Aura Block, and why he had come knocking on her bedroom door at that particular moment.
She eventually broke eye-contact and went eerily still.
"Martha, please say something," he muttered, after she had been silent for an extraordinarily long time.
Without looking at him, she handed him her empty teacup, and asked, "Have you got anything stronger?"
"Yeah," he said, taking the cup. He moved round behind the sofa and she heard clinking. When he returned, the cup was about half-full of Scotch.
"Thanks," she said, taking more than a sip. He let her contemplate for another minute or so, and finally, she croaked, "I'm sorry."
"No need to be," he assured her quietly.
"I had no idea."
"I know. It's all right."
"But it's just since Lazarus?"
"Yep."
She nodded, taking another mouthful of the warming brown liquid.
"And she said there's no way to reverse the... mixing-up of energies that occurred? There's nothing I can do to give it back to you?"
"Nothing that even the Oracle knows about," he said. "She likened it to mixing black and white paint; all you'd ever have was grey. She said the only way to fix my problem is if you stop. Or slow down."
"Slow down? What, like put the brakes on a runaway train? You know, it's not like this is happening every single moment I'm not with you," she snapped.
"I know that," he said. "I've had that bloody cube for over a week, and this is the first time I've noticed a change."
"Most nights, I'm like, this nice, normal person," she said, her voice starting to quaver. "I just... you know, lie down and go to sleep. There are just times..."
"It's all right, you don't have to explain."
"Sometimes, I can even fight it off. Sometimes it will hit me and I'll just think, ugh, not now, for whatever reason, and I just... move on with my life. I go to sleep."
"I get it, Martha," he said, placing his hand on her back. "I really, really do. I've been alive a long time, and I've been, well... unattached, in a manner of speaking, for most of it. Trust me - I've been there."
"You've had to live in close quarters like this, with someone you..." she stopped. "Think about a lot?" Her tone was sceptical and bitter.
"Yep," he said.
She took another swig, and seemed to try to get control of her emotions. But then she lost the battle. She buried her face in her free hand, and her whole body seemed to tighten. For a couple of minutes, he stroked her back and shoulder while she seemed cry tears that were nothing but bitter.
"Why are you crying?" he asked, actually only trying to be reassuring.
"Because," she whimpered. "I otherwise I might explode."
"Explode? Why?"
She practically shouted, "I don't know what to do or say next! I feel like I'm an exposed nerve, and you have a skewer in your hand! I feel like you're looking at my insides, inside my mind and soul too, and I have no recourse! I'm angry with you, and with myself! I'm angry because I can't turn back time or rewrite your memory."
"Why would you want to do either one of those things?"
"Because this is embarrassing, don't you see that?"
"Yeah, I see that. But Martha, please don't be upset," he said. "There's good news here. Now that we know it's something as benign as this, we can solve the problem together."
"Solve the problem? Together? Are you insane?" she asked, now properly shouting. Her face was streaked with tears.
"No, I'm not," he assured her. "I'm sorry, but I can't go on like this. I've lost track of time! A Time Lord with no sense of time is just a... Lord. And not the useful kind."
"Blimey," she breathed, and sniffled, sitting back against the sofa cushions. She finally looked him in the eye again. "So, let me get this straight. I... let's say, conjure an image of you - which, by the way, is more or less involuntary - and that takes energy from you?"
"Well, maybe not so much the image itself, but the... other things that go along with it. Whatever is going on inside your head, I'm assuming, is using not just images, but... say, invoking mannerisms, textures..."
"Your voice, your eyes, the way you move..." she added. She surprised herself. She reckoned she must be feeling the Scotch a bit. "I'm pulling it all from somewhere inside of me, which I suppose, is actually now coming literally from your energies."
"Right, and maybe some of what you're using is hypothetical," he suggested. "Extrapolating from what you do know, in order to hypothesise about what you don't know. That kind of synthesis would cause all parts of your right brain to tug at anything it could, concerning me. The first thing it can find is actual energy that you got from me."
She blinked at him a few times, and then mused questioningly, "Extrapolating... in order to hypoth..." Then she realised what he meant. "You mean, trying to work out what you'd be like between the sheets, based on what you're like when you're up and running about? That was a lot of posh words for fantasising."
He cleared his throat. "Erm, yeah. You know what? That might be enough Scotch for you."
"Yeah, I know, I'm a quick drunk." She handed him her cup, and he himself downed what was left. "So all of that takes something from you. I guess I can kind of see that."
There was a silence, while they both wondered what to say next.
And then, "Doctor?"
"Yes?"
"I don't know how to stop. I will try, but... I don't know how to discipline my mind that way, not without driving myself mad. I've never needed to, never thought it was beneficial to banish persistent thoughts completely. Even times when I said that I've been able to fight it off, I've always sort of embraced my angst, in some way. I've always thought that letting it burn would be what ultimately allows me to live with it more comfortably. Not just this thing with you, but any time I've had something on my mind that wouldn't go away."
"That makes sense."
"I mean... I would stop in a heartbeat, if it meant restoring you to full capacity, but like I said, it just happens once in a while. And sometimes, there's only one way to quiet my mind, and let myself relax enough to sleep."
"I know, Martha."
Her voice was rising again, growing supplicant. "It's how I feel... I can't help how I feel! Trust me, I've tried to shake this thing off! I've tried to just plough through it, but I can't! You're under my skin, Doctor, in a huge way. In every way. It's not something I chose!" She was sitting at the edge of the sofa now, practically pleading with him.
"Martha, I know!"
"So what do we do? You can't just take me home - it wouldn't solve anything. I'd still have my problem, which means you'd still have yours."
"You know what we have to do," he told her, gravely.
She threw herself back against the cushions, remembering the investigative advice he had said he'd received from the Oracle. "Really?"
"Martha, there are multiple options for stopping this thing, some of them less pleasant than others. Worst case scenario, I wipe your mind of all vestiges of me, and return you to Royal Hope on the day after the Judoon incident, none the wiser."
"What? Are you joshing me? I wouldn't remember you at all?"
"Worst, worst, worst case! But, best-case scenario, we find out that the energy you're taking from me isn't actually being depleted in the long-term, and we devise some kind of dampener that will let you sleep, and help me find my groove again. Maybe the answer is somewhere in-between. But in order to determine that..."
"You have to observe," she said flatly.
He shrugged, then took a pause and asked, "Would you rather I overreact?"
"No."
"I could just send you in to the Oracles' Abode for observation, if you'd prefer."
She narrowed her eyes, and frowned at him, and for thirty long seconds, she seemed to be thinking. Then she asked, "You'd have to watch?"
"In a manner of speaking."
"What do you mean, in a manner of speaking?"
"I mean, I can design an instrument that will measure..."
"Ugh," she groaned.
"What?" he asked.
For a long while, she stared exhaustedly at the wall, measuring her words. Then, "I'm not a phenomenon, Doctor. This is not a hurricane or a rock concert - you can't just set a thing in the room with me and hope it measures my... enthusiasm. You can't put a number on my feelings. You can't just..."
"All right, all right," he said, suddenly remembering what they were talking about. A flash of her, dishevelled as she was when she opened her bedroom door came into his mind. The flushed cheeks had been the tell-tale sign, the sure-fire signal of warmth that had made him tingle with sudden desire. "What do you suggest then?" His mouth went dry.
"This is an organic thing, Doctor. We are talking about something that lives and breathes in me, I suppose almost literally, and no machine will do it justice, not on its own. I don't want to know that you're somewhere, watching me on a monitor, like I'm a science experiment."
"Okay."
"Which means, if you're going to watch, then watch. Come in and observe. Be organic. Bring your equipment if you must, but the point is, we are sentient beings, you and I."
"You want me there?"
"No. But it seems more natural than having my body's most poignant internal musings measured by instruments."
They both had to have a few more swallows of Scotch before they could properly talk about how it would go. But they did manage to set out an agreement. How to get started? How to set up the equipment?
How was he to behave in the room?
"As though you're not there," she told him firmly. "If this is going to happen, I'll need to shut you out completely."
"You'll need to pretend I'm not there... in order to pretend I'm there?"
"Don't analyse," she snapped. "Just do it. Or the whole thing falls apart."
"What if I need to move about the room? Adjust things?"
"Do what you have to do, to get the information you need. But don't move unless you need to, and I won't take... you know... stage directions."
"What if..." he began, but then trailed off, ultimately taking another swig from the Scotch. They had dispensed with the teacup, and where now sharing the bottle.
"What if, what?"
"What if the whole thing just proves too much for me?" he asked, swallowing hard, trying to draw her eyes into his, desperately hoping she would understand what he meant. He didn't want to have to explain.
"Too much for you? What, like you can't bear to watch?"
"I don't think that can't bear it will be the problem," he said meekly.
"You mean," she said, smiling, but speaking with bluntness. "What if you like it a little too much?"
"Yeah," he whined, pulling one hand down over his face.
She sat up straight and looked at him squarely, blinking hard a few times. Then she said, "I actually have no idea how to answer that question."
But the first, and most difficult, order of business had been working out when. Would they just pick a date approximately ten evenings hence? Martha dismissed that notion, saying that it would make her too nervous if she knew the date was coming, and she might not be able, or want to "comply."
After much deliberation, it was decided that the only way to do it "organically" was, she would find a way to let the Doctor know when, on her own terms. In the meantime, he would devise some sort of apparatus that would measure the so-called damage she did.
And one afternoon after a pulse-pumping near-crash in a spaceship, the Doctor having diverted its course away from an asteroid using his unique powers of quick-thinking, shouting, and leaning on the throttle with all of his strength, she let him know. She went to her room and scrawled, "Tonight" on a writing pad, then slipped the note into his breast pocket, with a smile, and a little pat on the lapel.