Just something I wrote after the Christmas special, as I missed Clara terribly in the episode and I am a Whouffaldi and Souffez diehard shipper.

Past Memories

Ashildr burst into the TARDIS doors, entering the console room with a smile on her face.
'I think I managed to ward off the hydr-'
She stopped, finally looking up at the figure she could see just through the time rotors.
'Clara?'
The sound echoed around the room, finally travelling toward Clara, who hadn't been listening previously. She turned round, hastily wiping a stray tear from her eye before Ashildr could see her.
'Are you okay?' She asked with sweet concern.
'Yes, yes, I'm fine.'
'What are they?' She nodded her head to the things in Clara's hand that she was holding tightly to. She sighed.
'I...uh, I'm just reminiscing. Just some daft old memories.' She sniffed, fixing her a weak smile, yet she could clearly see the heartbreak in her eyes. Ashildr slowly made her way toward Clara

'I'm sure you made many.'

'Yeah...' She said, turning round and leaning against the console, 'we did.'
'She smiled fondly at the photographs in her hands, and the immortal knew she was trying to contain further tears. She had known how broken and depressed she had been after her children's death, and knew it was exactly the same kind of pain coursing through Clara's body.
She watched as she flipped through the photos, watching the smiles of a young floppy haired gentleman she assumed to be the previous Doctor kiss Clara's cheek as she laughed embarrassingly at the camera. She saw each photo of them together, sometimes laughing, sometimes lounging around on an alien planet or in costume of the particular time period they were in. She couldn't help but notice how young Clara looked, so much more innocent inside but still holding that brave and headstrong side of her she now observed everyday aboard their TARDIS. In fact, Clara had come to use the term 'Time And Relative Diner In Space', to her amusement.
And then the pile grew to the pictures of the older Doctor and Clara, of which she could see the same inseparable bond.
She noticed that these pictures were taken more inside the TARDIS, or Clara's flat, some of them portraying the young woman ruffle his fluffy, silver hair or a sneaky snapshot of the Doctor lying sprawled on the couch, fast asleep. With every picture Clara's eyes sparkled just a little bit more and her hands trembled when she rifted through the pile.
'It was hard...' She said, staring at one particular photo of her and the Doctor, arms around each other and Clara's cheek nuzzled against his red velvet jacket, 'letting go. When he looked at me and couldn't recognise me...that was the moment my heart broke. But I hope he's safe, and he's happy. That's all I want for him, and someone to look after him. If we had kept both our memories, we would never have rested. We would have split the universe apart to try and save each other. Too alike, two Doctors, one complete Hybrid. I knew it was inevitable in the end.'
Ashildr put a comforting hand to her shoulder.
'I am sorry, very sorry. I never meant for that to happen on Trapstreet. I never wanted you two to get hurt. But as you say, it was inevitable. And you pushed each other to the extremes, and yet you still made it to the end of the universe.'

'No, no, Ashildr, it was never your fault, I never blamed you. It was always meant to happen, time is fixed and I can't change what happened.'
'You speak a lot like him. And you fly the TARDIS...I don't know who was more the Doctor that night, you or him.'
'Oh, it will always be him. And I'll always have him here, wherever I go, and whatever I do. I remember the day I met you, Ashildr, that day in the Viking village. He told me that when I'm gone he won't be able to breathe and all the pain will catch up with him wherever he will go and it would always be there, constantly. I know what he means. I know the life of the Doctor, I finally understand how the loss weighs upon your heart and damages your mind. But the pain, oh the pain, Ashildr,' she said, this time smiling and turning her gaze to her, 'is so worth it. I wouldn't trade a single moment of our time together for a single fraction of a second. It was amazing and beautiful and overwhelming while it lasted. And I know that somewhere out there,' she threw her arm wide, gesturing to the closed doors, 'he is hurtling through time and space, probably already picking up a new companion, or with someone he loves, like River. And that keeps me going, that keeps me strong.'
'You loved him, didn't you?'
'She bit her lip, still staring at the pictures, 'yes, yes I did. And there was not a single moment when I didn't. I admit I loved Danny Pink for a time, but I wasn't in love with him. No one compared to him. Not my Doctor. I just hope he knows that. Even if he can't remember who I am.'
'Clara, I don't think he ever could forget you. I don't think he has.'
'Yes, I know,' she smiled weakly again, 'he knows who I was and where we went, but nothing about the way I smiled or laughed or looked. Not even when I was right in front of him. I hoped the music I played in the diner would stir a memory, which it did. But not enough to remember my face. And I swear to god, he better be enjoying himself and flirting with his actual wife or something. I'm sure he would have wanted the same for me.'
'He loved you too, you know. Everything he did, he did it for you, Clara. His expression was one of a man devoted to his wife, very inexplicable and powerful love. I could see it from the first day I met you, as my diaries told me.'
'We never told each other; it was more kept in the dark, like we knew it was there but never admitted to it. But, in truth, I don't care if he loved me or not, I did and I wouldn't have had it any other way.' She said, and there was a small pause in which Ashildr decided to tell her.

'I told him I knew he loved you,' she explained, 'well, not really like that. I stressed the word 'friend' quite a bit and how he decided to punch a diamond wall for four and a half billion years to save you only because he missed you. His face was a traitor to his words.'
'All I want is to treasure him, for all the heartbeats we shared together that lasted forever in my eyes. And I want him to embrace whatever comes, throw himself in adventure and remember that every Christmas is last Christmas.'
Another moment brought a reminiscent smile and the silence of appreciation of his demise. And then she turned, putting the wad of photos into her pocket and smiling at her, just like the Doctor did.

'So, where should we go? What should we see? All of time and space at our disposal.'
She grinned at the admirable woman before her, tapping the console with her fingertips.
'Wherever it lands us, you're the boss.'
She smirked, taking the leaver in hand.
'Yes, I am,' she said confidently, 'now shut up, allons-y. I have a feeling this one will be fantastic. Geronimo.' She exclaimed, pulling the lever down.
And with that the TARDIS launched itself through the vortex, and Clara smiled at her mischievously. Oh, she was definitely an embodiment of the Doctor.