I wanted to share an idea for a story that I had. I may get around to writing it, but if not I at least wanted the idea out in the wild as I haven't ever come across it before. Maybe it inspires someone else. Or maybe it's super common and I'm just a dumb ass. 

The idea is a simple one. Your owner locks you in chastity and tells you they've picked a number. They take this number and write it down and put it in a safe as proof of the number. It represents how many orgasms you're allowed to  have for the rest of your life. You can ask for an orgasm whenever you want. They will happily let you out of your cage and give you the orgasms in whatever way you please. But at some point you will use your last orgasm and when that happens you're done. The next time you ask for one they will bring you right to the brink of Cumming only to castrate you just before you can finish. Denying you. Laughing and telling you that the last time was your final time and how excited they have been seeing you squirming and anguishing between then and now. Trying to decide if they were gonna risk another one. Knowing that your castration date was due and that you would be the one to unwittingly decide it made them more aroused than they have ever been in their life.