An orgasm that is usually over the phone wherein one or both of the people on the phone orgasm without making any noise, usually because they are unconfortable with moaning or they think their partner is. You may experience this while participating in CPS, if not, you're a loser.
Joe: Dude, I was on the phone with Leann and she had a silent orgasm!
John: Really? How could you tell?
Joe: Well we were having CPS.
John: What is CPS?
Joe: You dipshit, look it up online.
John: Oo! Urban Dictionary dot com!