Try (TFP Optimus Prime/Orion Pax x reader)

Sleep/Warmth

I sat up straight. "Are you ashamed of your past self? Why do keep letting Megatron probe at your skin?"

I corrected myself. "Metaphorically."

Optimus looked up to the ceiling. "He was a file clerk. Who-"

"Prime, please stop."

"Stop?" He turned to you again, placing a servo on the slab and slightly lifting himself up.

I continued, more frustrated with care than anything. "Stop thinking both sides of you are different bots. Your name now was given as a title. You still value your creation name, don't you? Or is that something you gave up entirely?"

Optimus glanced to one side, before his optics traveled back to me.

"When one becomes a Prime, you become someone new in the optics of others. Your old self becomes, shame in it, disheartening or not, irrelevant. Especially since this war started, there's been no reason for..."

He suddenly trailed off, actually taking my previous questions into consideration.

I took the opportunity to give my opinion. "It was because of Orion Pax that you now call yourself Optimus Prime. I don't think you should let that name go."

He took a moment of thought before speaking. His attention kept on me. "You seem to care about this a lot."

I relented slightly. "Well I do. I believe that you, ether Orion or Optimus, it still you. I just think.. it shouldn't matter... Pax."

Optimus was surprised slightly, though I couldn't tell. He looked up at the ceiling again.

"No one has called me by my creation name since I was granted the power of a Prime.."

He sighed, admitting a little. "You're right. It's just me. A name. It shouldn't leave such bitterness."

I gave a smile of relief. "Expect me to be using both your names interchangeably."

He looked to me with a small smile. He layed down again, and I finally decided to do the same.

After some time Optimus spoke once more, but softer in his tone of voice.

"You still haven't explained why it matters to you so much in particular."

I sighed. 'I guess I have to tell him about it.'

He turned his helm to me, and I turned my head to him.

"Do you remember when I asked if you recall anything when you were your past self?"

"Yes?"

I closed my eyes. "Well... I remember."

"You... remember?" Optimus was curious to where this was going.

I was serious with him. "I was there. On the Decepticon ship. When you arrived."

"You were?" He was very surprised, and now wanting to know more.

"Yes. They caught me after you left the Autobot base. I don't think they expected you to find me. You were fascinated by me, and asked for Megatron's permission to keep me in your lab. He was super reluctant, but rationalized that you wouldn't remember me."

I abruptly sighed. This wasn't really going anywhere. "Can't you remember anything?"

All of a sudden, Prime felt immensely guilty by this new information he had obtained.

I sighed again at the guilt in his faceplates. "Not even a feeling? The song notes we shared?"

Pax blinked. "Songs?"