Mastery of the Phallus, including but not limited to jazzing the glass, taking in mass amounts of semen, riding wangs, eating cucumbers, jacking the jervis.
Pure and unadulterated Mastery over phallus and all it's functions. Often fellatio, Handjobs, taking in multiple Phalluses into a single orifice.
Man Britany acheived cockmastery last night, she took all four of our dicks and then swallowed like a gallon of cum.
Quiten attained cockmastery when he joined the Man-Navy last week.