up goes the donkey

Said to have originated from a travelling showman whose finale involved the hoisting of a donkey on a pole or ladder.

up goes the donkey

1. (obsolete) The performance begins.

• Used in conjunction with a required amount, to encourage the public to pay more money before the start of a show: e.g. "Twopence more, and up goes the donkey!"

• 1873, John Camden Hotten, The Slang Dictionary (under donkey)