a blunt that is reserved for special occasions. first you empty the tobacco out of the cigar without breaking it, then you stuff all the weed that you can into the unbroken cigar paper(usually a quarter ounce will do) by pressing it in with some object like a pen, etc. and finally you smoke it.
mike: yo, it only took me six years but i'm gonna finally graduate from high school.
shoal: oh snap! let's go smoke a grandfather blunt.
N. A third-generation blunt, having nothing to do with tediously stuffing an unbroken blunt wrap full of chronic. To make a grandfather blunt, first one must begin smoking first-generation ("normal") blunts and harvesting roaches. After harvesting enough 'resinated' weed from those roaches to roll another blunt, one would twist up with it, creating a second-generation blunt. One would smoke the second-generation blunt and save the roach, then repeat the process with enough second-generation blunts to roll another blunt. Once this final blunt is rolled, one has a grandfather, or third-generation blunt.
"If it takes the roaches of ten blunts to make a second-generation blunt, and the roaches of ten of those to make a third-generation blunt, then this grandfather blunt we are smoking required the smoking of 110 blunts to create."
"Wow, I'm getting really high."