It doesn't have to be scary...
There is a number of things you do in life which may be intimidating and the thought of actually saying it to the other person puts you in cold sweats. Asking your other half if he or she would be interested in locking up your cock can often create that sort of anxiety. However I'd like to reassure you that like many other situations we often over think the matter and actually you'll probably be surprised just how receptive your other half is to the idea.
So how to start the conversation? You've watched some videos, seen pictures, viewed cages online, but you don't know if a) your other half is even aware of the practice or b) they are repulsed or turned on by the notion.
Perhaps you want a softer approach and perhaps you wish to be more direct. If the former then I advise you look to a site which must be commended for for gently introducing kink to couples all over the world in a non threatening way. XRU is a kink VLOG held with regular guests from the kinkier side of the porn world who talk about a particular subject each time and then test out some of the theory on camera. They have done a few episodes on male chastity but their episode in season 1 is a good place to start.
This is a great site to use as a tool to introduce your OH to kinky play and here is an idea for you! Start on Season 1 episode 1, watching it with your OH, then within a few episode you'll reach the chastity episode so you can introduce it to them without heading straight for it. That way, if you don't want to seem overly keen but wish to start a conversation with them and gauge their reaction, you can do so while having some fun.
The episode i'm referring to is found by clicking HERE.
If you don't have time to spare or the thought of chastity is driving you mad then you want a more direct approach. Short of mind reading you're not going to know their reaction, and this may be what has put you off asking her or him about chastity in the past. Don't beat yourself up though, shared experience would suggest that people are naturally curious and will receive your suggestion or request with intrigue and excitement rather than disgust or shock!
In this situation the best way is to approach from the angle of having a chat about the dominant/submissive dynamic between you in the bedroom. If this dynamic already exists...great! it'll be easy to get started. If not then simply ask them what their opinion is on taking charge, perhaps they'll know what this entails, perhaps they wont. Either way you can move to the suggestion of there being certain 'things' that help establish this particular dynamic in the bedroom and even ways to take it beyond. That part is sure to peak their interest and you can develop that conversation by moving to talking about does the idea of having control turn them on and what level of control would be good for them? Ask them if they like the idea of controlling your orgasms, this is the most direct way you can ask without actually saying 'slap a cage on me!'.
From there it's more than likely their interest will continue to rise and the conversation will blossom, if they answer 'what do you mean?' then you can say you came across blogs like this showing how the male orgasm can be controlled and introduce them to the notion of chastity via the blog OR if they already are starting to get an idea of what you're hinting at, move straight on to the devices. Say you have seen some interesting looking toys that you'd like their opinion on then open up our store page to show them a wide range of chastity cages, different sizes and different materials and from there the fun can begin! Good Luck!