Withdrawing from the kiss if only to get a better angle, Megatron tangled his free hand with Optimus' cuffed ones. If he wasn't stroking Optimus' spike at the same time, he'd have tangled both his hands there, but this would have to do.

Keeping his optics on Optimus when his Prime caught them, Megatron grinned and twisted his hand, and despite the firm, encompassing, maddening clench, rolled his hips and then dragged out, unable to quite keep back the shudder at the feel of all those workings so firmly pressed up against his spike.

Oh, no, he wouldn't stop. Not this time.

So he'd hardly withdrawn before he slammed back in, giving a tug to Optimus' spike at the same time and idly noting that he soon would be hard-pressed to keep dumping charge elsewhere.

On the other hand, Optimus looked...

"It's okay. Let go."

Quite close.