I think it was supposed to be when Sal calls with his black voice or Richard calls up as Rusty to rankle whoevers in studio with some questions. But because it was Shuli, it was botched, unfunny, DOA, and went nowhere.
Like, I think George was supposed to have some big reaction to whatever Shuli was bringing up. But Shuli was barely intelligible with his dumb disguised voice, George just laughed it off and Howard abandoned the bit on the fly.
That's my take.