He'd go face-first for a lot more than just getting his Prime's panel open, but that would come when he did indeed get it open. Chuckling softly against the panel, Megatron followed first the outline, then down to where the pelvic panel ended at the hip joints with his lips. Something between kissing along the metal and mouthing at it.

It was... curious how quiet things were now, and all that could be heard, and he couldn't deny that it wasn't deeply satisfying to hear the soft, whining strain of Optimus working against the cuffs.

All that power, under his control.

Working upwards again, Megatron followed the outline of the details on Optimus' pelvic armour, briefly avoiding the panel itself until he'd mapped the rest out and then descended, laying several short, static-laced licks over the panel as he'd lightly charged his tongue.

This was just the beginning, and he'd have his Prime undone.