Soft as Marshmallows

“.... Why?”
The word repeated constantly in The Doctor's head. He couldn't understand it, like the many other things he couldn't understand in this dimension of magical Greek mythologies come to life. He hated knowing so little. He hated that he could no longer be the pool of knowledge he had been before he'd fallen into this world of 'Equestria'.
He'd read books upon books of this universes' libraries, knew all of their recorded history and their stars, their mysteries and achievements throughout all of time. And yet still there was so much that he just didn't understand. Mainly the magic of this world. Magic. He tried to convince himself it was a form of science, but just when it started to make sense, something new would occur.
Originally, the magic fascinated him. He wanted to know more, he wanted to learn. But after The Truth... There just seemed to be no point. Magic was magic, talking ponies existed, and there was no longer any reason to bother trying to figure anything out beyond that.
It was too dangerous. That's what he told himself. Everyone had a right to be afraid of the unknown, didn't they? Something so complex that even he couldn't understand was something he didn't want to touch. The sheer power that magic contained was enough to tell him 'No. Don't dive any further into this.'
He now paced about the TARDIS, alone with only the distant hum singing to him for an eternity. He told himself he would never leave, never take the risk... But something always managed to tug him outside into the small town of Ponyville. He'd made an exception to only travel within a 100 year gap and only in that general area that seemed to be the most safe and dull era of pony history.
'Why...?' he found himself asking again in his mind. He made his own rules, and here he was breaking them. His Sonic had warned him of his body's levels going all over the place, and he could physically feel it whenever it happened, and yet... Why could he never resist? Why could he never stay inside and ignore it? Why did he allow contact to the TARDIS and why was he responding to it so openly? And why did that silly little unicorn keep coming back? He'd denied her and yet there she was again, refusing to take 'no' for an answer, insisting he needed a hug for whatever reason. And then, and then...! Even after he'd acted upon an instinct, sure that it would chase her away from the mere vulgarity of it... She still came back!
His hooves clopped loudly on the TARDIS floor as he continued to pace in circles, huffing and unsure, his legs shaking and his ears folded down in frustration.
“What does she bloody see in me?! Why? Why does she insist? And why... Why me?” He stopped in place, looking down at his disgusting hooves. A reminder that he once had such wonderful hands at some point. He lifted a hoof and stared at it for a long moment. The offending hoof that he was sure would chase her away... “Soft...” was all he murmured under his breath as he continued to contemplate his next action.
The Doctor shook his head and sat down, continuing to stare. “She was... So soft...” He sighed deeply. It wouldn't hurt to see her again, would it? She was just another pony, after all. And besides, perhaps if he went along with what she'd asked, she'd finally stop. There could be a chance that maybe if he just pretended he was fine and that she 'fixed' him, she'd be satisfied. And yet, the fear was there, tucked in his mind, always beating out it's rhythm at him, screaming. 'What if she never stops? What if she falls for you? What if she wants to be a companion? What if she becomes just like the others? Lost forever in the life of adventure, taken by whatever terrible fate followed you at every corner? Like Martha, or Rose, or... Ditzy...?' The very idea caused him to collapse into a huddled ball of terror.
This was no ordinary visit. This wasn't a hug to make him feel better. This was... This was something that could only happen once in someone's life, something unrecoverable and precious.. And it was being offered to such a useless man and he didn't know why. And that was what scared him the most. Not knowing why.
But on the other hand... There was that dark suggestion in his mind, whispering as it always had been but ever so much louder than usual. Perhaps the experience would be fun? What did her feelings matter in this, really? He could try something new to ease all the tense imbalances in his body. Perhaps his lusts were hungering for something fresh, the same way they'd once did when he'd married the Virgin Queen for the soul purpose of breaking her title in history. Just because he could and because he wanted to show he had some sort of power over history, to prove he could do whatever he wanted. Of course, no one ever let him live the event down. He'd become quite renowned for his actions. All the more reason to try something similar with this unicorn who was throwing herself at him. She had absolutely no idea just how important she was to history, or just how tempting she was in general, and that darkness inside him wanted to take that for himself.
And yet... And yet! It all felt so wrong at the same time! The Time Lord put his hooves to his head and grimaced. He wasn't stealing anything, she was giving it to him. Willingly. He hadn't made the first approach like he'd done with the Queen, he had no plans, and he had no idea just who he was about to deal with.
“It's just a pony!” he insisted to the empty space that was the TARDIS. “She's just a harmless pony who is probably mixed up and doesn't know what she wants. No reason to be concerned.” He nodded assuredly, sitting up and patting a hoof to his chest as he tried to boost his own confidence, “Who she is doesn't matter, does it? She's soft. Very soft, and warm, and she will probably be good company in bed for a night. That's all I want anyways. That's all that matters.”
Still shaking, he managed to pull himself back up and trotted over to the TARDIS console, biting his lower lip in a mix of anticipation and nervousness. He was going to do it. He was going to accept her offer and there was nothing wrong with it. They both would get something they wanted and that would be that. No complications. They weren't friends, there was nothing special between them, so there was no need to make it a big deal. She probably just wanted her first time to be memorable, and what would be more memorable than having a go with a Time Lord?
With his co-ordinates set, the TARDIS was off, groaning as she always did when she was set to park somewhere new. His ears perked to the landing 'ding', and before he left the door he composed himself accordingly.