Wiktionary
pull the other one, it's got bells on
alt. (context idiomatic jocular English) (non-gloss definition: Expresses disbelief.) phr. (context idiomatic jocular English) (non-gloss definition: Expresses disbelief.)
Usage examples of "pull the other one, it's got bells on".
Now, 'pull the other one, it's got bells on', he'd heard of - it stemmed from the days of a crueller than usual ruler in Ankh-Morpork who had had any Morris dancers ritually tortured.