Boyfriend Hid an Extra Key for the Lock

Hello everyone. I could use some guidance. We’re just starting out here and have recently begun the routine of being locked for several days each week. My boyfriend got a CB6000s, which I bought him. Throughout the delivery period, he had to wear panties daily, with my promise that once he was securely locked up, he’d get his reward. He was hesitant at first but eventually managed to slide his little cock into the new device and lock it himself. Trouble started right then. Once he was successfully secured, I asked for the keys. He handed me just one. It seemed odd, but he claimed that’s all came with it. Since I wasn’t there when the box arrived, I couldn’t verify exactly how many keys were included without checking the manufacturer’s details myself. After some prodding, he eventually produced the second key. That evening, after plenty of teasing, he was finally unlocked and rewarded. A few days later, while he was complaining about wearing panties all day and being locked for short periods (I’ve been patient with him as he’s quite anxious about losing control, which I feel is generous), I spotted a hidden key in his office. When I called him out on it, he admitted he feared not having direct access to his own key and asked for forgiveness. Now that I have all the keys, I believe he deserves some punishment for lying and failing to fully commit to the gradual process of becoming locked up. Does anyone have suggestions for punishing someone who hides extra keys to their lock?