At this point he has to be desperate. Every edge has teased his body into thinking it would get it's release, only to be disappointed. His balls are swollen, filled to the brim with all that hot, sticky cum.
You're now at an impasse. As his mistress, and the owner of his pleasure, you could give him his sweet release. You could let him blow his load, pump his brain full of dopamine suppressors, and finally bring an end to the torturous ride of pain and pleasure.
Or, if you've found this new power intoxicating, you also have the choice of NOT ending it. You could lock his dick back up, plug his ass, and untie him. You could continue to tease him, build, sustain, and use his desperation. As long as there is the possibility of an orgasm sometime in the future, you will have an obedient little fuck slave that will beg for opportunities to please you: cook for you, clean for you, massage you, eat your pussy, whatever your wicked heart desires. This could go on for hours, days, weeks even!
Until now, this possibility probably hasn't crossed his mind. It's time to change that and decide his fate...