I am not forbidding you from having an orgasm; I am simply taking away the control from you. As my submissive, it is not up to you to decide when and how you cum. That decision belongs solely to me.
It's important to remember that the release from chastity is a privilege, not a right of yours. It is not something you can demand or expect, but rather something that I can choose to grant you as a reward for your obedience and devotion.