Keep them soft

I'm a straight, married 29 year old alpha, and I recently found your site. Even though I'm straight, I've been using gay guys for years since they can take a much more intense and brutal fucking than any of my girlfriends ever could. However, I HATE it when a fag's little dick gets hard when I'm fucking it. It's such a turn off. I tried a cock cage once, but didn't really like seeing that down there either, and also I don't use my fags very regularly. It's more just a hookup every now and then. It can be a few days between or even several months, and they know not to contact me in between, so I can't be managing its chastity.

Any ideas on how to instruct them to keep their dicks soft? Or maybe I need to punish them when they don't, but I'm worried the little fuckers will enjoy that and only make the problem worse.