Dominating your Man: An Introduction
Put the chastity device in his hand, walk behind him, and pull the blindfold off. He will likely not know what it is immediately, so have some fun explaining it to him. Tell him that it is a chastity device and that now he doesn't have to worry about you teasing his cock just to deny him over and over again. Make him thank you for being so generous ;)
Now you could just ask him to put it on and be done with it, but what would be the fun in that?! Instead, make a game of it! Tell him that he can put it on himself, but every minute that the key isn't in your hand gets him ten spankings in a place of your choosing. Since he can't be hard if he wants to put it on, this could prove to be quite difficult. For each round of spankings, try different areas of his body and/or different implements.
Once the cage is on and the key is in your hands, he will have no choice to but to obey you without question...