written by Doug Moreland, ASCAP (composer/author and publisher)
(from Urban Dictionary)
To lock oneself away with a musical instrument and practice, either a particular piece or in general, until the player has improved greatly or can perfectly play the piece he has been practicing.
Due to the many hours he spent woodshedding, Jon became a better guitarist.
True story - Doug's mother told him to go practice his fiddle out in the yard where she couldn't hear it!