PLAY THE F***ING BASS JOHN

"PLAY THE F***ING BASS JOHN"???  I was at last night's show and when the band was being introduced and it came time for John, Simon kept repeating it and so did the crowd.I vaguely remember the story behind it ( I know that Simon said it to him during a show some time ago, right?). Can you give me the whole story behind it? Steve

"Steve, No big story, it's just an evolving ad lib thing...JT"