Sasha is he ok with this decision?
Kaja What we need is caution in actions.
Ines When someone writes "I want to put" to other person on chastity and the other person has the age of your son, no, it is not your forum.
This, this and this. You do not just "put someone in chastity". That wording implies that you would not be giving them a choice. Messing with another person's genitals without taking their own needs and choices into account is abuse, even if they are your own son or daughter. No, especially if they are your own son/daughter, as you would be basically using a power imbalance to fulfill your own wishes. And abuse of minors is both immoral and can land you in some serious hot water legally.
If you want someone to wear a chastity device for you, the only defensible way to go about it is to encourage them to accept it for themself. Convince them of benefits without pressuring them, and figure out terms they can agree to.
Why do you want him in chastity anyway? Is it a conviction of yours that he does not necessarily share to the same extent you do, or is he at risk of some self-destructive behavior?