Sexual discipline, for Me, is the crux of the practice of this intimate art of Dominance and submission. I work in the opposite direction. My love generally is more likely directed to cum than not to. If she doesn't? Then I'd be likely to have her cum more and under more extenuating circumstances in a way of enhancing discipline in reminder of "why" I do what I do and say what I say.
We do a lot of anal-play. I'd suggest having him insert a butt-plug and then perhaps a cock-ring (dare I say gates of hell???) and then work him - with a heavy load of red applied to his ass! Work him out sexually, get him bothered and delay, delay and then - blow his mind out - then? Have him toy with that plug and as he does, have a nice, intimate talk with him as he tugs on his balls and stretches his bottom about the "how and why of the how and why". One thing which is delightful about cyber is? What we say is "it". The level of trust is so intimate, or can be. That is why I'd been more focused on the discipline, not the punishment. Learning to give you orgasmic control and You learning to wield it involve "discipline". You already have made great progress I'd say, because the MOST IMPORTANT THING IS - He was honest with you! So I'd say you have the control, honor his respect by working him through this in a way that he WANTS to be more disciplined because he knows there is tremendous joy in it for him in the end. Your pleasure at being served and given the timeless experience of having Control ought to give him deep satisfaction and I'd guess lead to some rather large "releases" in time, no?