(adjective) When a woman is "on the rag", that means she has her period. She's also likely in a bad mood because of the various discomforts associated with pads, leaks, tampons, washing out underwear, not being able to wear light-coloured skirts or pants, etc.
She's really in a mood, she's on the rag and complaining about everything. Last night she slept so soundly that she woke up in a pool of blood.
When you have to pee in a movie but don’t want to miss anything, and must do the following mental equation: will the amount I have to pee cause enough discomfort to diminish my attention capacity for the remainder of the movie to an extent which is greater than the amount of the movie I would miss by making a mad dash to the restroom.
I saw Satantango last night, wonderful film but by the 5th hour I had to start doing pee calculus.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).