1)He should be shaved. Yes, that's right, his pubic hair should be shaved off and he should keep himself smooth and stubble free from now on. This is none negotiable and should be understood from the beginning.
2)Right after he shaves for the first time, have him sit on the edge of the bed, lie back and pull up his knees. You're going to stick your finger into his ass. Yes, you're going to finger fuck him. You will need a rubber glove and some lubricant, Vaseline, butter, olive oil, whatever. He is going to be extremely embarrassed to present himself to you in this fashion, his anus is a very private spot, not seen or touched by anyone. That is why you're doing this. Once he is in position and holding his cheeks apart, lubricate your middle finger and his asshole and slowly press your finger to his opening. Slowly start to enter him. Look into his eyes as you penetrate him. Talk to him and have him talk to you as you both experience his submissiveness to you and this act of penetration.. Think about what he is allowing you to do, he's naked, shaved and your finger fucking his ass. Pull on his cock and balls as you slide in. Go in as far as you can, slowly. Look into his eyes when you are in all the way and tell him you are in all the way. Ask him how he likes it.. This may be the first time you are inside his body, enjoy the power exchange.
3)He needs a good cock teasing at least once a day. This doesn't mean he's going to have an orgasm, in fact he is not. But he needs to be hard and brought to the edge of an orgasm at least one time a day, either by you, or for you. "For you", means brining himself close to orgasm and stopping. Yes, this means masturbating for you, on demand. Two things here. One, he must learn to tell you he is about ready to orgasm and ask you to stop and he must learn to masturbate for you, and stop. Orgasm control is a powerful psychological aspect for a submissive man, and you too will learn to enjoy your teasing and control. It is another important power exchange with you controlling the single physical aspect of maleness that is maleness alone, a hard cock and orgasm at will. This also means that unsupervised masturbation must end, and he will only orgasm with your permission. Orgasm denial is part of this teasing
4)Nudity, him naked, you dressed. This should be done at awkward times, odd times, whenever you like, when he least expects it. Obviously if you're going to tease his cock, make him strip. Make him strip even if you are not going to tease him. If he doesn't usually sleep naked, he should now. In fact, anytime he is in your bedroom he should be naked. At some point, make sure you bring him to every room in the house naked. Lead him to each room naked, by his cock, the basement, laundry room and garage, all will now hold memories of your control
5)Nudity outside is more problematic, but should be attempted. Start with outside of your home late at night. Be careful to pick a night when you know your neighbors are away. Again, at night put him in the passenger seat of your car and tell him to strip. Put the seat all the way back. Pick some back roads and drive slowly and carefully, and DON'T drink. If you like, a highway may give a glimpse of his nudity to a trucker. He wouldn't like that, you may. Reach over with one hand and keep him hard reminding him not to cum. Don't stay out long, fifteen minutes should be enough. Pick a secluded place where you can stop to allow him to dress so he doesn't interfere with your driving.
A nude beach could also be fun. He will be naked of course and you should be in your swim suit to emphasize his submissiveness. Remember he is shaved, so anyone who sees the two of you walking together knows who's in charge. How embarrassing would a hard on make this? The object here is to be seen by as many as possible, so walk, don't sit in the sun. Well you can sit on the beach and enjoy the sun, but not until everyone has seen him naked.
6)Embarrassment is also part of the fun obviously. Be careful not to embarrass him or yourself in font of friends or co-workers. This must be done carefully and for the fun aspect of your dominance. Ordering wine and his dinner at a restaurant is a simple start, and one he will enjoy. While with friends for drinks or dinner, whisper in his ear, "what do you think they would think knowing you're shaved, knowing I own your orgasms". After his yearly physical ask him if the doctor said anything about his shaving.. If he works out in a gym, ask him if other men are shaved and what they look like, are they big, circumcised, big balls, small balls, compare them to him. If you have one girlfriend you can trust, and you probably don't, arrange an "accidental" flash. Remember, it only appears as an accident to your girlfriend, your guy might not like it but he'll cooperate. He is in gym shorts and a tee shirt and that is it. You can grab him and tickle him in front of your friend, accidentally pulling down his shorts exposing him, then after all the hooting and hollering, pull then all the way down and step on them. He will have to step out and run. Remember, he knows this is coming so he may be hard, and of course he is shaved. You can have a quick laugh with your friend and tell her you better see if he is OK. Go to the bedroom, strip him, grab his cock and lead him back to your girlfriend, saying, "well you have already seen him naked, you may as well get a better look." Doing the same thing in front of a couple would be more than twice as embarrassing.
7) Proving his submissiveness can be tested with the above situation, but should also include most if not all of the list to follow.
You should orgasm much more than he does. That goes without question, his submissiveness definitely translates into you cumming more. You need to teach him how to orally please you better, and as often as you like. I know this may seem odd, but a tongue up your ass will feel great, and he wants to do it for you, so tell him that is now a part of your oral pleasure. Don't worry, you don't' have to do it for him.
Back rubs, foot rubs, leg rubs, body massages, anything you think you might like you should try, and then do as much as you like. He loves every minutes of doing anything for you, especially if he is physically close to you.
Help with house work, yard work and generally being a better partner is assumed. He can also learn to cook with your teaching. He is not your slave, but he can be a more than a 50% partner in the house holds chores you don't like doing. Delegate, delegate, delegate. He will not do things if you don't tell him to do them, and show him how you want them done. He can't read your mind, so tell him when he is doing something wrong, but more importantly tell him when he is doing something right, and ask him to do it again.
It's not all about sex but a lot of his submission is. You need to talk to him and ask him what turns him on or off. Ask him what he expects and wants. Tell him what you expect and want. Keep an open mind and don't freak out if he has some silly fetishes. He is sharing everything with you and no one else, so even if it seems pretty odd or nasty, try it, make him do it, whatever.
There is only one thing that all submissive men must learn to do. You should have this conversation with him in a none sexual environment, so the reality of the requirement is finite, unequivocal and a given. Every time his orgasms, he must consume his ejaculate. That's right, you heard me correctly. If he ejaculates in you he must lick you clean. If he ejaculates on you, he must lick you clean. If you masturbate him or he masturbates for you, you must feed him his semen. At some point you should make him shoot into a cup or a glass and he must drink it down. This requirement for all submissive men does two things. It puts a real price on his orgasms, and it shows your acceptance of your dominance, and his acceptance of your dominance, no matter who brought the topic up. This is none negotiable and should be explained to him when he first approaches you with his desire to be submissive to you or your desire to lead the relationship. If he does not accept this simple requirement, he is not submissive. It is the only test and proof that he is sincere in his desire to be submissive, and your only requirement showing you are to assume the leadership role in the relationship.
There is much, much more of course, but you will discover things along the way. These are just a few suggestions but a good starting point for exploring this new aspect of your relationship. The most important thing is to have fun. If he approached you, he has a need. If you approached him, you have a desire to change the course of your relationship. Either way, if it is done in a loving fashion, it will be fun and bring you closer. So enjoy.