It's been 25 days of being locked up, at the start you swore you'd never suck dick, but a strap on doesn't count, right? Now that its the only way to earn release, you hope it still works.
You knew they were also locked when they asked to lock you up, but you had no idea they expected you to match the time they already had in their belt, and since she was Ace it wasn't difficult at all for her to last the 3 years she already had.
You always thought you had problems with being insensitive down there, however, it would appear you just jerked off too much and lost sensitivity, 2 months in chastity fixed that.
First you wore panties, then you dressed up, now you are locked in a cage that you lost the keys for and there is only one way left to feel release. Let's hope you are a fast learner.