I know you can handle your little plastic cage, but it is your birthday today and I want to give you a special gift.
Locked in this metal device, including your balls and of course the insert that goes all the way in your cock.

No escape, total control by me and every time you get hard the metal will be merciless and you will be in a world of pain.

Don't worry it is not all bad, I will tease you every day so you can enjoy my beautiful body.