In the past, Optimus thought that opening his chest plating would be extremely difficult for him, no matter who he was with. Simply put, Optimus was a private mech, and respected those he was close to far too much for… something like that. But that didn't stop him from fantasizing, sometimes. Nothing ever came of it, but they were harmless daydreams that flitted through his processor from time to time.

The last place he had ever imagined he'd find his chest armor splitting at the seams and coming apart in was a Decepticon brig, under the "loving" ministrations of a cruel seeker, who was being especially cruel in his kindness. Every mocking stroke was as good as a slap in the face, and so it surprised Optimus when he felt his chest opening; so much so that he jerked his gaze downward even as Starscream did, nearly banging their heads together at such a close distance.

It was a distance that would prove fatal for even the powerful seeker, for it wasn't Optimus who had parted his chest plating from the inside.

The matrix shone gleaming around his spark, tucked in front of it like a shield as it bared itself to Starscream. Optimus knew this because he could see it reflected off both the seeker's canopy glass and his astonished optics. Before either had time to act, the matrix grabbed its Prime's spark- sudden and surprising enough to force a startled shout from Optimus where torture had not- and pushed it forward, manipulated it. Optimus lay frozen, terrified despite the waves of reassuring warmth that spread through him as the matrix pushed his spark, sending tendrils of its energy licking against the seeker's canopy beseechingly. He could do little but clench his fists in horror at the sudden feral, hungry grin that spread across Starscream's face, the mocking smirk that followed as the seeker parted his own chestplates, from inward out until the glass split along a seam lengthwise and folded neatly away.

It was a trap.

Quicker than either could follow, the matrix gently pushed the Prime's spark back once more, and lashed out at the seeker's now-exposed spark, pressed up against it as he was. It latched on with an almost violent ferocity, and with a startled and panicky shriek, Starscream collapsed, limbs twitching, over the prone and restrained form of the Autobot leader. Optimus was afraid for a moment, thinking that the matrix had somehow been tainted, changed, that it was killing Starscream in the most frightful way possible.

Starscream's shaky moan and slowly pawing hands put that fear to rest. The flier was still alive, and making sounds that mortified Optimus at such a close distance. He could just barely feel what the matrix was doing, connected as they were, and from what he could tell the matrix was practically suckling on Starscream's spark. There was no other term for it besides the human one, and oddly enough that disturbed Optimus more than the entire situation.

Staring at the Decepticon second-in-command's twitching wings in his line of vision, Optimus wished he could feel nothing. This was, frankly, disturbing.

Finished (with a satisfied feeling that left Optimus recoiling), the matrix released the poor seeker with an audible electric pop! – and then courteously closed the Prime's chest plates again, leaving Optimus with a passed out, exhausted, overheated Decepticon recovering on top of him.

There were some days he hated being Prime.