Invented by TomMace on Casey Neistat's Youtube Channel, to "smack it" is to put the work in, commit to it, and to not go back.
Casey: Dan, I really don't feel like doing that timelapse today
(Dan wakes up)
Dan: Huh???
Casey: I said, "I don't feel like doing that timelapse today"
Dan: Aw c'mon dude, let's smack it
Committing to a task. If someone says "im going to smack it" they will, with no exceptions do the task.
Example: Casey felt tired and didn't want to edit, but then he's said "I'm just gonna smack it dude"
Casey felt tired and didn't want to edit, but then he's said "I'm just gonna smack it dude"