"
Smooth move" is a sarcastic comment in response to a stupid or crass action and "
exlax" is a pejorative reference to the perpetrator of such action. The whole term comes, of course, from the fact that
Exlax enables smooth bowel movements.
The insulting capability of "
smooth move exlax" runs the gamut from a mild put down (as to an friend who just said or did something reasonably stupid) to a scathing remark on the inane actions of a worthy idiot.
To a friend not watching were she is walking and who runs into a sign post: "
Smooth move exlax"
OR
To a submoron who realizes he was about to miss his freeway exit and proceeds to cut across three lanes of oncoming traffic, causing angry motorists to brake and nearly crash: "
SMOOTH MOVE,
EXLAX!"
