(informal) a cigarette containing marijuana (= an illegal drug)
~ (sth) (up) (into sth) to make sth/yourself into the shape of a ball or tube: [vn] I rolled the string into a ball. We rolled up the carpet. a rolled-up newspaper I always roll my own (= make my own cigarettes). [v] The hedgehog rolled up into a ball.
To learn how to roll a joint, see:
YouTube - Learn To Roll A Joint - Training Video
Student or Learner