This figure of speech grew popular at El Molino High School. A not-well-known way of saying, "You're pulling my leg." Originated from the saying "I'm just joshing you." Named lovingly for the Nickelodeon show "Drake and Josh." Also makes sense, since Drake always got Josh into horrible situations.
"Dude, my mom just died."
"Nuh uh? Let me buy you icecream."
"So, anyway, my mom isn't really dead, man. I was totally draking your josh."