When you tell him
Now tell him he has to cum in 30 seconds but alone, not with your help. If he had betrayed you once by cumming without permission (which I hope he did) then reduce the timer to 25 seconds. Deny him for 2 days between each session. Ask him if he wanna ejaculate (not cum). He will surely answer YES.
Then, the next day will be your first milking day. you'll get ready to go to work or whatever and ask him to get naked and you will tie his hands behind his back. You'll stroke his cock and when he cums just drop it so he ruins his orgasm in front of your clothed body. You will do it on the days between the training sessions. So one day training session if unsuccessful the next day milking session. All right!
Another thing! after a few days, you will say that you miss your sexual life but you want to fulfill his dream. So you want him to give you an orgasm by cunnilingus. Every day after the training session, he will have to perform a good cunnilingus if he wants to cum the next day.
Oh a small detail. you will not shave your pubic hair during this period. Sooner or later he will make a remark about it. Answer "Ok I'll shave if you shave too". He might have difficulties to do it so tell him that you will help him in the process.
When your slave has no longer any hair below his shoulders you may continue.
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