The growing rumbles of Optimus' engine and the field of his spark could easily be felt through the glass plating and the rest of his frame, and it only picked up as Cliffjumper began to touch him in return. Optimus used it to his advantage, leaning just close enough to the smaller red frame to let their plating rattle together with a pleasant vibration.

Letting out a low purr against the minibot's mouth, Optimus changed the kiss again; lapping out with tongue, tracing Cliffjumper's lips, eager to see his reaction.