Sack Lantern
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!
sack-o-lantern
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!