At this point, the gag would stay not just to make sure he wasn't urged on, but to stave off said anger.

Humming into the kiss, Megatron twitched and rolled his hips, ignoring the aching of other parts as the re-routing/dumping routine he'd set up carefully let only a part of the charge they were building up stay around and in his spike.

Withdrawing fully, a feat that might have been harder to accomplish if Optimus hadn't been tied with stasis cuffs to lessen the strength of those delightful thighs, Megatron grinned and nibbled on Optimus' lower lip and closed his free hand around his Prime's spike.

Twisting his hand and rubbing the head as he snapped back inside again in one smooth stroke, he could at least ignore the charge dancing about his hand. It was built a lot more sturdily than his mouth, after all.