You've been locked in chastity for a long time now. You've been such a good boy, abstaining from pleasure for me, so I thought I would give you a reward.

No! I'm going to unlock you, nothing like that, but I think you'll still like it.
Now, with it being so long having your cock locked up, you're probably out of practice when it comes to stroke. That's why I want to turn you on to a different type of orgasm, a prostate orgasm. It is my sincere hope that you like it so much, you'll never want to stroke your cock again.