In computer video game terminology the mouse-finger is the dominant, or preferred, finger the video game player uses to wield their most valuable implement of destruction, i.e. the computer mouse. Without one's mouse-finger one is completely helpless.
Joe: *Crack* Damn!
Mike: Hey Joe, why the expletive?
Joe: I just broke my mouse-finger. I won't be able to finish the Unreal Tournament.
Joe: Your passing will be remembered in our myths and legends for years to come. Rest in peace.
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).
Precedes or follows either a gratuitously disrespectful or honest remark, originated in New York City. Used in similar fashion to "no offense" or "to be honest," interchangeably.
Ya mans is wild buns, respectfully. Respectfully he's washed.
After school, The Modells on Jamaica Ave was active. Respectfully.