caught with your pants down

[dansillysod]

what does coaught with your pants down refer to?

[shaneystar2]

It means to be caught unawares ....surprised in the act of doing something or something that you shouldn't be doing in the first place.

http://ancienthistory.about.com/b/a/195143.htm

Though I very much doubt that Caracalla wore trousers !

[jno]

caught in an embarrassing (but not necessarily shameful) position, taken by surprise, caught in a position where you're unable to run away...

[albatross521]

caught red handed.

smoking gun.

but not commiting a crime.