Northstar Optimus Prime x Fem Reader

10, Blood test

Opening my eyes I was met with an unfamiliar ceiling. This one  was grey and way lower. Huh? Sitting up I started to recognize my surroundings. The inside of Optimus's ult mode. Then,

"Like you're really pretty... and lustrous, and I want you to step on me."

Oh fuck. What the fuck. I said that. To Optimus Prime. Oh fuck. What do I do?!?

Looking around I discover that we're not in the hanger, but the medbay for the Transformers. Of course, Optimus knew my distaste for the doctor in the humans bay and that I don't want to go unless it's necessary.

What my eyes landed on was confusing to say the least. It was Optimus's bipetal form. But I'm in his ult form right now... Oh yeah, and he's SHORT. Well short compared to his cybertronian form, but this shorter version was almost seven feet tall...

What?

I scrambled to the front seat to get a better look. Next to him was ratchet, who was also a human height, and also his bipetal form. Optimus' head immediately went to his ult form sitting about 20 feet away. Oh yeah, he can feel every movement I make...

"Um... why are we here? And why are you so fucking short?" I snort, laughing at the once titan.

"I suggest you come out here." Ratchet responded in a serious tone through the comms, in that instant I knew something was up.

"What's going on?" I could hear the worry in my own voice,

"Do not worry Y/n, if you get too uncomfortable we will stop." Optimus offered, the drivers side door popping open

I was reluctant to get out, but I had nothing better to do. I slowly stood out from the car, walking to the other end where Ratchet and Optimus were standing.

"So, what's the matter?" Ratchet and Optimus looked at me, then back at each other before looking down at me.

"So..." Ratchet trailed off as if unsure how to begin, "How many times has it been now?" He asked, still in a cautious tone of voice.

"Uh- What?" I questioned, confused and a little frightened,
"How many times have you taken these drugs?" I could tell Ratchet just wanted to make sure I saw that he was genuinely curious and needed some sort of answer.

I glanced down, trying to find something, or anything to say as my eyes bouncing between the two holoforms.

"... You mean recently or all together in my whole life?" I shyly ask, Ratchet looked a little taken aback.

"Recently."

"Only twice. The first time was a few hours after Optimus... You know, and the second was last night, which a certain someone witnessed." I gestured to Optimus,

"Alright. Optimus, what was she like?" Ratchet wrote some notes in a data pad or something.

"Almost identical to a sparkling."
"A what?" I question, Ratchet raised a brow.

"It's what humans call, a child." Ratchet answered, writing more stuff down. I pause, and turn to my guardian.
"Give me one reason to not kick you in the dick." I cross my arms, Optimus raised a brow.

"It would not help the situation, or any situation." Optimus answered matter factly,

"Oh nonono, there's absolutely situations where punching someone in the dick would help."

"Anyway," Ratchet cuts in, "We need a blood sample from you Y/n."

"Why?" I raise a brow skeptically,