to mess up or screw up badly. to make a mistake.
person 1: i can’t believe you forgot to pack our passports for our trip.
person 2: yeah, sorry, i really did burn the garf with that one.
To “burn the garf” is to mess up badly. A big screw up.
Person 1: “I can’t believe you forgot to bring your passport on the trip!”
Person 2: “Yeah I really burned the garf on that one!
Person 1: yeah well don’t burn the garf again!