*The Michael Jackson Estate is through with Conrad Murray running his mouth — talking about things like how he used to hold MJ’s penis every night — and is now demanding he stop yapping … or face a lawsuit.

According to TMZ, MJ Estate lawyer Howard Weitzman fired off a cease and desist letter to Murray earlier this week, writing, “Your recent comments to the media about Mr. Jackson’s medical treatment and ultimate death shamefully violate the physician-patient privilege under California law.”

He calls Murray a coward for attempting to use the media to defend himself instead of testifying in court during his manslaughter trial.

If Murray keeps talking, Weitzman says the Estate will not only file suit, but also inform any medical board with which Murray attempts to obtain his medical license that he regularly violates the doctor-patient privilege.