Dominating your Man: An Introduction
Look at him writhing, exhausted from all the stimulation. Tell him how much fun you've had, and you don't know if you want it to end. Put the chastity cage on his chest and tell him you could just lock him back up and keep him. Ask him if he would like that: to be caged, plugged, free to draw your baths, rub your feet, and lick you to orgasm after orgasm, all without worrying about cumming. If he says he likes the idea of that, then maybe you should consider obliging. If he begs to cum instead, remember that's against the rules...
If you decide to lock him back up, then let he'll need to get limp. You can offer to help: get some ice, hold it on his dick, maybe pop a few pieces in his asshole for good measure. Once you manage to slide it on and lock it, tease him about where you might put the key for safe keeping. You could freeze it in a big block of ice or throw it in the backyard without looking so you wouldn't be tempted to let him out.
Finally, you'll need to plug his hole back up. Tell him that you're worried about his plug falling out after his rough pounding. Then, grab the bigger plug, set it on his chest, and lube it up. Press it against his asshole, tell him to take a breath, then slowly slide it into his ass. Now he is ready and willing to tend to your every need.
If, on the other hand, you decide that he's had enough, then continue on...