When she cries out, Knock Out raises his head and the look he gives her is absolutely wicked. His frame tremors pleasantly at the touch of her hands along his helm; his optic rings diffuse a little, gratified. His fans have spun up too, louder in the confines of the corridor than they had been in the open nighttime air, though he has the presence of mind to reverse his ventilation system so that they expel through his dorsal ports instead of washing hot air over Rogue in such close quarters.

Unthinkingly, he saves that vocal clip to memory as well. How can he not?

"Did you know," Knock Out begins with damnable pleasantry, like they were in the midst of holding a typical conversation rather than carnal activity. "That 99% of the human body is made of just six elements?" He dips down again to take another long lick, this time along her opposite thigh. It has the same effect as the first, another surge of high-charged current radiating from the path.

And then he continues, still conversationally, "Carbon, of course. Oxygen. Hydrogen and nitrogen."

Lick. "Calcium." Lick. "And phosphorus."

His optics once again are luminous, his biolights refractive. "These all make you electro-conductive, which is interesting since—" He wraps gentle fingers under one of her legs, giving her something to brace against and spread wider for him. "—Since Cybertronians are electro-active."

This time, his tongue swipes directly through the lush wetness that's gathered there.