You can just give him the key, tell him to shave and wash real good. Give him permission to stroke it some and enjoy his erection but warn him against getting carried away or he's in BIG trouble. When he is done and comes back to you (he will still be erect, I promise) have the condom ready, unrolled half an inch or so with numbing gel/spray already inside (you can't really use too much). You can massage the liqid/gel around inside once you roll the condom down. Now would be a good time to let him go down on you and instruct him to slowly edge himself while pleasing you but let him know all fun stops if he gets carried away. After about 15 minutes it will be safe to let him get carried away as he wants. He wont be able to get off while having sex but you when you are done, you can encourage him to do his best with his hand. He will be MAD with lust and the desire to cum so just let him go until he tires out and cant go anymore. Then, tell him to wash up with soap really well and tell him he has 10 minutes to try and get off inside you but he isn't allowed to stoke himself with his hands anymore. Be dramatic and set a timer on your phone and set the phone next to the cage and let him know he has 5 minutes (set the timer again) to recage after the timer goes off to get his cage back on and present to you for relocking or he will get swats with the cane.