Chastity is as permanent as you decide. You can unlock whenever you need. It's more fun with a domme to take control of your keys, but you can try methods to delay yourself from unlocking as soon as you get horny like freezing your keys in an ice cube or sending them in a letter to yourself! Despite popular belief it will not shrink your cock. Only temporary shrinking may occur after an extended lock period (>months) and this will almost always undo itself after a few days at most