"Chalk It Down" is generally used by stoners in Ireland, it can mean various things, too many to even list but people use it as a substitute for "chill" or "ok" or "in your face"
Example 1:
Girlfriend: Are you messing around with Lisa???!!!
Boyfriend: Whoah Chalk it down! (chill)
Example 2:
Boy1:You coming to the party tonight?
Boy2:Ya, i'll be there @ 9, chalk it down! (ok)
Example 3:
Boy:I fucked your 'ol doll last night, ha chalk it down! (in your face)
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.