By this point, Enver knows that right now he is delaying what is probably the inevitable moment where this stops being the kind of oral he knows how to do and simply becomes face-fucking, and he doesn't know how well he's going to be able to control teeth or gag reflex once it reaches that point. The most that he can do is what he can, while he can, to prove there is something worthwhile in not pushing it to that point.

He can go further, and he does. Adjusting the placement of his jaw, broadening but also focusing the movement of his tongue, seeking out every vein, every sensitive crevice. Meanwhile keeping his hand working.

He's out of practice, not that he was exactly studied in such things to begin with. So he can only go with what he already felt drawn to do. Let that fuel him, keep it burning hotter than that mote of panic that is now threatening to overpower it.

He doesn't dare pull back; he's not even certain the Dark Urge would allow him, even if it is just to move on him, to simulate that thrust.