To place a flashlight on your sack and shine light up through, creating a redish glow or lantern effect
Remember that time Nick did the Sack Lantern and then Luke stuck the flashlight in his mouth?" "Ya man Luke took that Sack Lantern!
by nickvanl April 11, 2011
A sack-o-lantern is when you place your ballsack on someones head and shine a flashlight through them.
Shut up or I'll sack-o-lantern you!
by Necroscope March 30, 2005