It's the best thing to keep a cuck in check. Keeps him calm, drained and limp at all times. I am very grateful to be milked regularly by my wonderful wife. She is very strict that way. The idea is to completely drain a man's prostate fluid by applying constant pressure on his prostate without penis stimulation, erection or orgasm. Massage the prostate until a steady flow of fluid will start dripping from your limp cock. Once all the fluid is drained masturbation is futile as you cannot cum for quite a while.
It can be done by hand but better results are achieved using a special device. She uses this one on me:
https://www.meo.de/en/cumelot-*****...search_query=milk&results=12#full_description
Takes some practice at the beginning to learn how to let go but once you get used it becomes second nature.