There’s a fun game in here, if you take out some of the fantasy.
Definitely tied up, then edging him with the simple rule, ‘If you cum without permission I ruin it, and I cage you up without release for X days (I’d go for something like 3 but tastes will vary!).
Then, see how well he can beg, what he might offer to be allowed to properly cum, have fun finding out how long he can last without going over. And then, in most cases, take him over anyway, ruin him, so he stays nice and horny, then put the cage on before untying him.
You could of course, let him cum… but he’ll prefer it if you ruin it, I promise.
And if he does last an impressive time, offer him an alternative – caged without cumming at all, but just for a day or two.
It’s not really his choice anyway, he’s tied up, and you have the key. So decide what you’d prefer!