A slang expression from the US Army, it originated during the Vietnam War and may be derived from the Vietnamese “di di mau", meaning to go quickly. Usage by American troops altered the meaning somewhat so that it referred to walking with dance steps or with an exaggerated swagger. It was used in the context of walking carelessly whilst on patrol in enemy territory, without paying proper attention to your surroundings and putting yourself and other members of the patrol at risk. The meaning later expanded to include moving or acting without considering other people.
OT mean Out Trapping or just out of town or somewhere and boppin or bop means a good beat or just a good song but together means Out here making a good beat/song.
Friend:Where you been g
Rapper:nothing g just been out here OT Bopping