How to begin.
Once you have your chastity device, you should engage in a brief test period. YOU should put it on him. Let him wear it for a day, then check to make sure there are no major problems. That is, make sure it doesn't pinch him or chaff him anywhere. If it does, try to correct the problem. You may also have to wait a few days for him heal before testing it again.
To prevent chaffing, use a good lubrication on his penis before putting it back on. Most water-based lubes will dry out too quickly. I suggest a oil-based or silicone-based lubricant. (Johnson & Johnson makes a Baby Oil Gel that works well for this.) If chaffing still occurs, you may have to resort to a different chastity device. Once he can get through a day without any problems, try it for twenty-four hours. If all goes well, try three days this time.
Once you have a device that he can comfortably wear day after day, be sure to clean and inspect it (yourself) at least once a week. Taking a shower together is good way to do this, but by all means, not the only way. The device does NOT need to be removed for cleaning. Use a liberal amount of soap and water to clean his penis every few days. Remember, he probably can't see it well enough to clean it himself, so you inspect it for him. This can be part of the teasing process as well.
Don't let him (or anyone else) tell you that he needs to have an orgasm to prevent ANY kind of disease. He doesn't! I checked with more than one doctor on that, so trust me. He can easily go for a week, a month, even six months or a year without having an orgasm. When the sperm in the body gets old, it will be released inside the body and will be quickly absorbed by the rest of the body. All this happens without him even knowing about it.
Blue-balls is something that is vastly misunderstood as well. Blue-balls is a condition that occurs when a man gets frequently aroused, but does not have an ejaculation for a long period of time. How long depends on the individual and the amount of arousal. What happens is this: He gets aroused and his body (testicles in particular) begin producing sperm (or fluids for feeding and transporting the sperm (in the case of a vasectomy) along the urethra for eventual ejaculation. If that ejaculation does not occur, there is a build up these things in the body (particularly the balls). This may cause him to feel a slight aching in the groin (or balls) when he gets his next erection (or tries to). It is harmless. It's all a part of the game.
After a few weeks of not getting have an orgasm, his body will limit the amount of sperm etc. that it produces and the effects of blue-balls will go away. (No more groin pain.) So you see, blue-balls is nothing to be concerned about. In fact, you may take some joy in the fact that he gets them. After all, it's just another reminder that he is yours and is not allowed to cum without YOUR permission.