the same or similar phrases:
(1) behind bars: in prison.
(2) behind the bar: in the 4th stanza, meaning behind the bar counter
(3) behind the bar: in the 7th stanza, meaning behind the bar restaurant.
(4) Monkey Bar: the name of a bar. There is an actual bar named like that on the 54tg street in NYC.
(5) monkey bar: a sport instrument on which people use their arms to move across.