If you've been to writing conferences, or network with other writers, you know what this means:
There are other variations:
There might be others that I haven't heard, but these come to mind. Frequently. Like every day.
Sit Butt In Chair
Get Butt In Chair
Butt in Chair
They all mean the same thing:
Sit down and write.
Don't move from there until you've written something. Anything. Even if it's crap and you're positive you're going to delete it. (Chances are you probably will.) That's okay, because if you hone that idea, create that perfect scene, develop that character even just a bit, you've had success.
Writers write. For a real writer, there is no "Someday I'm going to write..." Those words are for dreamers and wannabees. As Yoda might say, "Dream not, do."
Writer Warriors, get ready for battle!
And when you win and have written more than a grocery list, reward yourself. I highly recommend a cookie.