1. To create a rhythm by tapping, knocking, or lightly striking something. A noun or pronoun can be used between "rap" and "out." He rapped out the secret sequence that allowed him to enter the hideout. She rapped a beat out for me while I freestyled on the bus.

2. To utter a particular message or line in or as a rap performance. A noun or pronoun can be used between "rap" and "out." He rapped out a few lines about his life in Detroit and the oppression he felt from the police. I find that rapping my problems out can be pretty therapeutic.