To accidentally click on the wall post bar instead of the comment bar while facbookcrastinating and posting a private joke to both parties friends list!!!!!!
An idiom, generally used when referring to teachers, describes when a person looks extremely mad at someone else or yourself, and they (in their head) "click a pen", ready to write someone up, or explode on the offender later.
Did you see the way Mr. Rogers was looking at me? He totally just clicked a pen in his head.
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.