Failed inspection

I told Lukey to wear someone slutty under his jeans to work. You know something with lace. Something that would be nothing more than a slutty fuck toy for daddy. But when he got home I told him to show me what he wore. He swore he forgot and just put on a normal pair. He told me It would never happen again. To make sure I made him lock up his dick and spank himself. He was so embarrassed when I told him that I was going to post it here so everyone knows he made a mistake. Maybe next time he will try harder to remember. How long should I keep him locked up for?