I agree with a lot of what's been said above. Chastity and Diapers have some similarities and can potentially work together really well, lending themselves to similar headspaces. I really enjoy the helpless feeling of waking up caged, knowing I can't just hump away my horniness. Waking up caged AND in a wet diaper elevates that feeling to a whole new level for me, I can't even feel what I'm humping!
You can be encouraged or forced to wear both by yourself/partner/dominant "you're not going anywhere without locking/padding up!", and they can both work for humiliation "I hope they didn't see my cage/diaper!".
Both chastity and diapers can also affect you over time and rewire your brain. Wearing chastity can change where you focus getting your pleasure from, can help on the journey to an anal orgasm, and in some cases/fantasies can even temporarily shrink your willy. I'm less experienced with diapers, but I know they can also affect your bladder control depending on how you use them. So both lend themselves to a sense of progression (or regression, depending on how you look at it).
As for what cage I'm wearing, I'm sporting a black Cobra Chastity Nub. I like their open and lightweight (plastic) design, though I find it a little more tricky to wet myself in such a small cage. Might try sizing up when padded.