Lots of ways to do this
We hit the keg with 40 psi for 3-4 days checking every day and adding more to keep the keg at 40 PSI
Then when you want to serve you dump the pressure or most of it until you cant
get any beer. then keep hitting the keg with 2-3 psi at a time until you get a good result.
I was married for 10 years before my wife knew I drank.
Then one day I made a mistake and came home from work sober