Welcome to your new world. Luxuriate in your post climax. If you want, hold your man tight and tell him how you feel. Let him know if he did well. Relax and enjoy.
Now let's cement the deal and make sure that your man knows who is in charge - and who gets decide when he gets to cum. Tell your man to kneel and rub his cock nice and slowly.
Go and get a pair of your panties - they will be for your man to wear for the rest of the day and to sleep in. Ideally they should be smooth and satin, but whatever is fine as long as he knows they are panties you have worn. Take your time picking out a pair. Enjoy the thought of how he will feel putting on your panties.
When you ask him to put them on, make sure he knows that you want him to wear them (whether you care or not) and that if he wears them for the rest of the day and during the night, he will get to cum during the next series.
Let him know that he is still a man and that you understand that he normally would not wear panties (whether or not this is true does not matter). The goal here is to ensure that he feels loved, masculine, while also being totally subservient to you. Every time he moves and feels YOUR panties on his cock, he will think of your power over him and he will stay erect and horny. This is our goal.
Once he has put the panties on, rub his cock through them until he leaks a wet spot through them. Keep him excited about wearing your panties. Let him know that you sometimes get them wet too. When you are ready, please continue.