When one puts on their best formal tone whilst speaking on the phone, oftern resulting in a higher pitched sound and usually rather different to their normal speaking voice.
Rupert: Yo K dawg whats going on Friday man?
Kendall: Chillin' man, might roll a blunt...
"RING RING"
Rupert: "Hello, Rupert speaking how can i help you?"
Kendall: Check out the Pattersoning you fag!