The story
A reference to a gag in slapstick comedy theatre plays where a character’s trousers fall to the ground, exposing his underwear, to elicit laughs from the audience.
Etymology from Wiktionary, CC BY-SA 4.0.
whoops, there go my trousers
whoops, there go my trou·sersToday it means: Used to describe a genre of farcical theatre plays. Full definition →