"Then you'll do it untouched," Vrenille says, having learned enough about Mustang to add this small bit of "cruelty" into the play of the scene. His pace has started to speed up again, and though it's not at the outright gallop it was before, with his voice so close to his ear, Mustang will certainly be able to hear the way his exertion and enjoyment both increase, degree by degree. His breath is now a sharp little exhale with each thrust, words peppered in between, and his hand continues to cradle Mustang's throat--just enough pressure there to constrict without cutting off his airflow.

"You'll do it with nothing but my cock in you to get you there. And if you cum, don't think I'm gonna stop or give you a break. Not till I'm done using this tight little hole of yours, not till I've dumped my load inside you."

It's the kind of shameless dirty talk that would make a lot of men blush, but it's also part of this little journey they're on together in which Vrenille is, step by step, teaching Mustang both something about the culture of the city and about his own inclinations to submit. And here's another layer of it--Vrenille isn't telling him not to cum. He's not forbidding it. They aren't at a place where his words would--or should--have that kind of control yet. But he is telling him the consequences, what he can expect should he lose control, and he's leaving it up to him how he'll handle that knowledge. Maybe the thought itself will send him over the edge or maybe it will give his body the incentive to last a little bit longer.